Effects of low-volume high-intensity interval training (HIT) on fitness in adults: a meta-analysis of controlled and non-controlled trials

High-intensity circuit training improves cognitive performance independent of changes in sBDNF levels in active college students

High-intensity circuit training (HICT) is an exercise modality converging aerobic and resistance exercises executed at high-intensity interspersed by recovery periods. During the HICT, the participants use their body weight as resistance. The impact of HICT on metabolic and cardiovascular markers has been reported, the effect of HICT on brain function remains unknown. The current study was focus to evaluate the impact of 24 HICT sessions on the serum BDNF (sBDNF) levels and cognition skills in young adults. Fifteen college students (22.1 ± 5.3 yr.) were randomly assigned to a control (CTRL) (n = 7) or a HICT (n = 8) group. The CTRL group continued their daily activities without restricting their physical activities, the HICT group carried out 24 HICT sessions. The sBDNF levels of all participants pre- and post-HICT intervention were determined by ELISA method. Visual memory, verbal memory, semantic verbal fluency, and attention were evaluated with specific neuropsychological tests. The heart rate variability (HRV) was recorded at rest in the supine position (5 min) for both groups at the beginning of the HICT program and 24 h after the intervention. The sBDNF levels increased in both groups at the end of the study (p < 0.0001). Visual memory (delayed recall) and long-term verbal memory significantly improved after HICT (p < 0.01). The HRV was unchanged by HICT. In conclusion, HICT might be a feasible method to improve cognition abilities in active young adults, and it is becoming a good option for college students since the intervention did not induce physiological stress in the participants.

The effectiveness of metabolic resistance training versus traditional cardio on athletic performance: a systematic review and meta-analysis

Introduction

The "no pain, no gain" philosophy has long influenced athletic training approaches, particularly in high-intensity workouts like metabolic resistance training (MRT). However, the necessity of discomfort-inducing training for optimal athletic performance remains debatable. This systematic review and meta-analysis examined whether MRT provided comparable or better results than traditional training methods in trained athletes.

Methods

A systematic search of PubMed/MEDLINE, Web of Science, Scopus, and SPORTDiscus (January 2004 - December 2024) identified RCTs comparing MRT with traditional training in athletes. Two reviewers screened studies and assessed bias risk using Cochrane RoB 2. Random - effects meta - analyses were conducted for outcomes like VO2max, peak power, sprint performance, blood lactate, time to exhaustion, and jump height. GRADE was used to evaluate evidence certainty.

Results

Eleven studies (n = 276 participants) met inclusion criteria. MRT demonstrated a statistically significant improvement in sprint performance (SMD = 1.18, 95% CI: 0.00 to 2.36, p < 0.0001) and countermovement jump height (SMD = 0.80, 95% CI: -0.04 to 1.64, p = 0.0007), indicating notable gains in explosive power. VO2max improvements were observed (SMD = 0.30, 95% CI: -0.19 to 0.79, p = 0.10) but did not reach statistical significance. Peak power output showed a moderate but non-significant positive effect (SMD = 0.54, 95% CI: -2.05 to 3.13, p = 0.55), while blood lactate changes varied widely (SMD = -1.68, 95% CI: -8.58 to 5.22, p = 0.29), reflecting high heterogeneity across studies. Time to exhaustion presented a small positive effect (SMD = 0.23, 95% CI: 0.00 to 0.46, p = 0.18), but without statistical significance. Subgroup analyses revealed that younger adults (19-25 years) and experienced athletes benefited the most from MRT, with low-frequency training (≤2 sessions/week) yielding the most favorable adaptations. Moderator analysis confirmed that sprint performance had the strongest response to MRT, while aerobic measures exhibited more variability.

Conclusion

The evidence demonstrates the capacity of MRT to enhance athletic performance comparable to or exceeding traditional training methods while requiring reduced time commitment. These findings suggest that optimal performance adaptations can be achieved through well-designed MRT protocols without necessitating excessive training volumes.

Systematic Review Registration

https://inplasy.com/inplasy-2024-11-0024, identifier: 36 INPLASY2024110024.

State-of-the-Art and Future Challenges for Nutritional Interventions in Facioscapulohumeral Dystrophy: A Narrative Review

Facioscapulohumeral dystrophy (FSHD), the second most common inherited muscular dystrophy in adulthood, is characterized by progressive muscle loss, accompanied by an increase in fat mass. Beyond these alterations in body composition, which contribute to the risk of sarcopenic obesity, FSHD is associated with systemic inflammation and oxidative stress. These interconnected mechanisms may worsen muscle atrophy, leading to a decline in physical efficiency and quality of life. While the therapeutic benefits of physical therapy and exercise have been investigated, the impact of dietary interventions remains underexplored. Given the established role of nutrition in managing various chronic diseases, there is growing interest in understanding how it might influence the clinical management of FSHD. By addressing current gaps in the literature, this review aims to investigate the potential role of dietary patterns and specific nutrients in modulating muscle metabolism within the context of FSHD. Some studies have indicated various compounds (flavonoids, curcumin, L-carnitine, coenzyme Q10, and omega-3), vitamins (C and E), and minerals (zinc and selenium) with antioxidant and anti-inflammatory properties as promising treatment strategies for FSHD. Instead, few data regarding the effects of proteins and creatine supplementation are available. Furthermore, the potential benefits of essentials amino acids, β-hydroxy-β-methylbutyrate, and vitamin D in contrasting muscle atrophy and enhancing muscle function remain unexplored. Despite these preliminary findings, the existing body of evidence is limited. Identifying novel therapeutic strategies to complement existing treatments could provide a more comprehensive management framework, aimed at improving the long-term health outcomes and quality of life of FSHD patients.

The Comparative Effects of High-Intensity Interval Training and Traditional Resistance Training on Hormonal Responses in Young Women: A 10-Week Intervention Study

BACKGROUND

Hormonal levels in women are influenced by exercise intensity and modality.

METHODS

This 10-week study compared high-intensity interval training (HIIT) and traditional resistance training (TRT) in 72 young women. Hormonal levels (estrogen, testosterone, FSH, prolactin, and LH) were measured pre- and post-intervention.

RESULTS

Both groups showed significant increases in estrogen (HIIT: 150%; TRT: 72.3%) and decreases in testosterone (HIIT: 58%; TRT: 49%), FSH (HIIT: 6%; TRT: 7.7%), and PL (HIIT: 5%; TRT: 2.1%). There are no significant changes in LH.

CONCLUSIONS

HIIT and TRT effectively modulate hormonal profiles, potentially benefiting reproductive and metabolic health.

Physiological adaptations and performance enhancement with combined blood flow restricted and interval training: A systematic review with meta-analysis

OBJECTIVES

We aimed to determine: (a) the chronic effects of interval training (IT) combined with blood flow restriction (BFR) on physiological adaptations (aerobic/anaerobic capacity and muscle responses) and performance enhancement (endurance and sprints), and (b) the influence of participant characteristics and intervention protocols on these effects.

METHODS

Searches were conducted in PubMed, Web of Science (Core Collection), Cochrane Library (Embase, ClinicalTrials.gov, and International Clinical Trials Registry Platform), and Chinese National Knowledge Infrastructure on April 2, with updates on October 17, 2024. Pooled effects for each outcome were summarized using Hedge's g (g) through meta-analysis-based random effects models, and subgroup and regression analyses were used to explore moderators.

RESULTS

A total of 24 studies with 621 participants were included. IT combined with BFR (IT+BFR) significantly improved maximal oxygen uptake (VO2max) (g = 0.63, I2 = 63%), mean power during the Wingate 30-s test (g = 0.70, I2 = 47%), muscle strength (g = 0.88, I2 = 64%), muscle endurance (g = 0.43, I2 = 0%), time to fatigue (g = 1.26, I2 = 86%), and maximal aerobic speed (g = 0.74, I2 = 0%) compared to IT alone. Subgroup analysis indicated that participant characteristics including training status, IT intensity, and IT modes significantly moderated VO2max (subgroup differences: p < 0.05). Specifically, IT+BFR showed significantly superior improvements in VO2max compared to IT alone in trained individuals (g = 0.76) at supra-maximal intensity (g = 1.29) and moderate intensity (g = 1.08) as well as in walking (g = 1.64) and running (g = 0.63) modes. Meta-regression analysis showed cuff width (β = 0.14) was significantly associated with VO2max change, identifying 8.23 cm as the minimum threshold required for significant improvement. Subgroup analyses regarding muscle strength did not reveal any significant moderators.

CONCLUSION

IT+BFR enhances physiological adaptations and optimizes aspects of endurance performance, with moderators including training status, IT protocol (intensity, mode, and type), and cuff width. This intervention addresses various IT-related challenges and provides tailored protocols and benefits for diverse populations.

Effect of self-paced sprint interval training and low-volume HIIT on cardiorespiratory fitness: the role of heart rate and power output

Aim

The primary aim was to assess the efficacy of self-paced sprint interval training (SIT) with low-volume high-intensity interval training (LV-HIIT) when performed without encouragement on improving cardiorespiratory fitness (CRF). A secondary aim was to explore whether the effort exerted during protocols [power output (PO) and heart rate (HR)] influenced the change in CRF.

Methods

In a randomised cross-over design, 82 previously inactive adults (m/f: 26/56, 28 ± 10 years, BMI 25 ± 3 kg m-2) undertook 6-weeks of self-paced SIT (4-8 × 30 s with 120 s recovery) or LV-HIIT (6-10 × 1 min with 1 min recovery) separated by a 4-week washout period. Sessions were completed 3×/week using WattBikes, and a target of >80% HRmax was suggested during the intervals. Markers of cardio-metabolic health were assessed before and after each intervention.

Results

Training increased VO2peak (SIT +3.1 ± 0.4 mL kg-1 min-1, LV-HIIT +2.7 ± 1.2 mL kg-1 min-1, P < 0.001) and decreased body fat % (P = 0.002), aortic pulse wave velocity (P = 0.002) and glucose tolerance 120 min following an oral glucose tolerance test (P = 0.024), with no difference between protocols (P > 0.05). When grouping participants into tertiles based on HR and PO responses (n = 27), those achieving a low HR had similar changes in VO2peak compared to the high HR group in both interventions (P > 0.05). For LV-HIIT, participants in the highest tertile for peak PO had a greater change in VO2peak compared to all other participants (Low 1.8 ± 4.1 mL kg-1 min-1, Medium 1.9 ± 3.3 mL kg-1 min-1, High 4.3 ± 3.6 ml kg-1 min-1, P = 0.020).

Discussion

Six-weeks of self-paced SIT and LV-HIIT induce comparable improvements in CRF, body composition, arterial stiffness and glucose tolerance. Importantly, higher HR did not elicit superior changes in CRF, but PO achieved during LV-HIIT may influence improvements.

Impact of Lower-Volume Training on Physical Fitness Adaptations in Team Sports Players: A Systematic Review and Meta-analysis

BACKGROUND

A small number of reviews have explored lower- versus higher-volume training in non-athletes, but the growing challenge of congested schedules in team sports highlights the need to synthesize evidence specific to team sport athletes. Thus, the objectives of this systematic review with meta-analysis are twofold: (i) to summarize the primary physiological and physical fitness outcomes of lower-volume versus higher-volume training interventions in team sports players; and (ii) to compare the effects of lower-volume training with higher, considering the training modalities used.

METHODS

We conducted searches across key databases, including PubMed, Scopus, SPORTDiscus, and Web of Science. We included team sports players with at least a trained or developmental level, focusing on studies comparing different training volumes (lower vs higher) within the same research. Lower volume training was defined in comparison to another load, emphasizing smaller training volume in terms of repetitions, duration, or frequency. The studies had to examine key physical performance adaptations and use two-arm or multi-arm designs. Methodological assessments of the included studies were performed using the Rob2 and ROBINS-I instruments, with evidence certainty evaluated through GRADE.

RESULTS

The initial search yielded 5,188 records, with 17 articles deemed eligible for the review. There was a non-significant trend favoring the higher-volume training group over the lower-volume group in resistance-based training when considering all pooled physical fitness outcomes (effect size - 0.05, 95% CI - 0.19 to 0.09, p = 0.506, I2 = 0.0%). A meta-analysis was not conducted for aerobic-based training due to only two studies being available, with one showing that lower volume training improved maximal oxygen uptake by 3.8% compared to 1.3% for higher volume, while the other indicated that lower training volumes enhanced performance by 1.6% versus 0.8%. The evidence certainty for physical performance outcomes was very low.

CONCLUSIONS

In newly introduced resistance training, lower volumes-regardless of repetitions or frequency-can achieve similar fitness gains to higher volumes. More pronounced tapering also appears more effective for supercompensation. However, the variability in study designs and training methods makes it difficult to establish a clear minimal dose. The main contribution of this review is mapping current research, providing a foundation for future studies and training optimization.

Meta-analyses of the effects of high-intensity interval training in elite athletes-part I: mean effects on various performance measures

Introduction

Meta-analysts have found that high-intensity interval training (HIIT) improves physical performance, but limited evidence exists regarding its effects on highly trained athletes, measures beyond maximum oxygen uptake (V ˙ O2max), and the moderating effects of different types of HIIT. In this study, we present meta-analyses of the effects of HIIT focusing on these deficits.

Methods

The effects of 6 types of HIIT and other moderators were derived from 34 studies involving highly trained endurance and elite athletes in percent units via log-transformation from separate meta-regression mixed models for sprint, time-trial, aerobic/anaerobic threshold, peak speed/power, repeated-sprint ability,V ˙ O2max, and exercise economy. The level of evidence for effect magnitudes was evaluated based on the effect uncertainty and the smallest important change of 1%.

Results

Compared with control training, HIIT showed good to excellent evidence for the substantial enhancement of most measures for some athlete subgroups in practically important study settings defined by effect moderators (maximum of 12.6%, for endurance female athletes after 6 weeks of aerobic traditional long intervals). The assessment of the moderators indicated good evidence of greater effects as follows: with more aerobic types of HIIT forV ˙ O2max (+2.6%); with HIIT added to conventional training for most measures (+1.1-2.3%); during the competition phase forV ˙ O2max (+4.3%); and with tests of longer duration for sprint (+5.5%) and time trial (+4.9%). The effects of sex and type of athlete were unclear moderators. The heterogeneity of HIIT effects within a given type of setting varied from small to moderate (standard deviations of 1.1%-2.3%) and reduced the evidence of benefit in some settings.

Conclusion

Although athletes in some settings can be confident of the beneficial effects of HIIT on some measures related to competition performance, further research is needed. There is uncertainty regarding the mean effects on exercise economy and the modifying effects of sex, duration of intervention, phase of training, and type of HIIT for most measures.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=236384.

Comparative analysis of the effects of high-intensity interval training and traditional aerobic training on improving physical fitness and biochemical indicators in patients with non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), linked to sedentary lifestyles and metabolic dysfunction, is highly prevalent. Exercise is an established intervention, but the relative efficacy of different exercise modalities remains unclear. The aim of this study was to compare the effects of moderate-intensity continuous aerobic training and High-Intensity Interval Training (HIIT) on physical fitness, biochemical parameters, and liver function in NAFLD patients.

METHODS

Sixty NAFLD patients (32 males, 28 females; age: 49.7±8.7 years; BMI: 31.1±3.3 kg/m2) were randomized into HIIT, aerobic training, and control cohorts. The HIIT cohort performed 4-minute high-intensity intervals at 85-95% of peak heart rate, interspersed with 3-minute active recovery at 60-70% of peak heart rate for 30-40 minutes per session. The aerobic training cohort performed continuous exercise at 60-70% of peak heart rate for 45-60 minutes per session. Both intervention cohorts underwent 12 weeks of supervised training, thrice weekly. Before and after the intervention, assessments included cardiorespiratory fitness, muscular strength, flexibility, lipid profile, liver enzymes, inflammatory markers, insulin sensitivity, and oxidative stress markers.

RESULTS

Compared to controls, both exercise cohorts showed significant improvements in cardiorespiratory fitness, muscular strength, and flexibility. However, HIIT elicited superior enhancements in cardiorespiratory fitness and muscular strength. Biochemically, both exercise cohorts exhibited reductions in triglycerides, low-density lipoprotein (LDL) cholesterol, liver enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST]), inflammatory markers (C-reactive protein [CRP], interleukin-6 [IL-6]), insulin resistance (homeostatic model assessment of insulin resistance [HOMA-IR]), and oxidative stress markers (malondialdehyde [MDA], protein carbonyl). Notably, HIIT yielded more substantial improvements in these parameters.

CONCLUSIONS

HIIT and traditional aerobic training are effective in improving physical fitness and ameliorating biochemical indicators in NAFLD patients. Notably, HIIT appears to be more advantageous in enhancing cardiorespiratory fitness, muscular strength, and metabolic, inflammatory, and oxidative stress profiles, suggesting its potential as a time-efficient and effective exercise modality for managing NAFLD.

Effect of a Modern Palaeolithic Diet in Combination with a Sprint Interval Training on Metabolic and Performance-Related Parameters in Male Athletes: A Pilot Trial

Background

Although a palaeolithic diet promotes healthier food choices that aid in weight management and reduce cardiovascular risks, its effectiveness in endurance sports is still debated due to its typically low carbohydrate content.

Objective

This study examined the impact of a 6-week palaeolithic diet (PD-G) versus a mixed diet (MD-G), both paired with Sprint interval training (SIT), on various metabolic and performance-related parameters.

Methods

Body composition, time trial (TT) performance (covered distance during a 60-minute run on a 400-metre track) and changes in metabolic (respiratory exchange ratio [RER], substrate oxidation rates) and performance-related (time at ventilatory threshold [VT] and respiratory compensation point [RCP], maximum oxygen uptake (V̇O2max) and time to exhaustion [TTE]) parameters during a ramp incremental running test were assessed in 14 male endurance athletes. Additionally, Gastrointestinal Quality of Life index (GLQI) and perceptual responses to the diets [visual analogue scale (VAS)] were measured.

Results

After 6 weeks, both groups improved in TTE and distance covered in the 60-minute TT, without significant group differences. In the PD-G body weight, fat mass and systolic and diastolic blood pressure decreased. At rest, RER and carbohydrate oxidation significantly decreased in the PD-G, with a tendency towards significance during exercise, while changes in fat oxidation rates were not statistically significant at rest and throughout the exercise test; in contrast, the MD-G exhibited smaller changes across these parameters.

Conclusion

In this investigation, a palaeolithic diet in combination with SIT appeared to have positive effects on fat mass, blood pressure and substrate utilization under resting conditions in a group of male endurance athletes. However, based on the current findings for performance metrics, a palaeolithic diet cannot be recommended unreservedly for healthy endurance athletes.

Effect of high-intensity interval training and moderate-intensity continuous training on blood lactate clearance after high-intensity test in adult men

This study compared the effects of High-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on blood lactate clearance. 21 adult males were equally and randomly assigned to the HIIT and MICT groups, and completed 8 weeks of training. Before the training intervention, after 4 weeks and 8 weeks of training, all subjects were tested for blood lactate levels between 0 and 55 min after the same high-intensity test. The results show that after 8 weeks, blood lactate levels were significantly lower than pre-tests in both the HIIT and MICT groups at "0-55 min" after high-intensity test (p < 0.05), and the blood lactate clearance percentage at15-min and 30-min in both groups were significantly higher than the pre-tests (P < 0.01). The blood lactate levels in the HIIT group were significantly lower than those in the MICT group at 15 min and 30 min after test (P < 0.05), and the blood lactate clearance percentage at 30 min in the HIIT group was significantly higher than those in the MICT group (P < 0.05). In conclusion, both HIIT and MICT enhance blood lactate clearance in adult males post high-intensity test, with HIIT demonstrating superior effectiveness, making it a viable alternative to MICT.

Effects of combining a high-intensity interval training programme with a standard programme on mobility and function in lower limb amputees

High-energy expenditure during walking is one of the most important limiting factors for lower limb amputees. Although several physical training methods have been proposed to reduce energy expenditure, little is known about the effects of high-intensity interval training in lower limb amputees. This study aimed to test the effects of a 6-week high-intensity interval training protocol in subjects with lower limb amputation on walking distance, physiological cost of walking, and functional mobility. A quasi-experimental pre and post-study included 13 subjects with lower limb amputation. They performed 12 sessions of a high-intensity interval training protocol with a frequency of 2 days/week for 6 weeks. Walking distance, physiological cost of walking, and functional mobility before and after the training protocol were assessed. Walking distance increased from 204.48 to 229.09 m ( P  = 0.003), physiological cost of walking decreased from 0.66 to 0.31 beats/m ( P  = 0.001), and functional mobility improved from 30.38 to 33.61 points ( P  = 0.001). High-intensity interval training improved walking distance, physiological cost of walking, and functional mobility in subjects with lower limb amputation.

Effect of high-intensity interval training on cardiometabolic component risks in persons with paraplegia: Results of a randomized controlled trial

The aim of this work is to determine the effect of upper-body high intensity interval training (HIIT) on cardiometabolic risks in individuals with chronic paraplegia. Twenty-seven individuals (14 females, 13 males, mean ± SD age: 46 ± 9 years) with chronic paraplegia (spinal cord injury between T2 and L5 >1-year post-injury) took part in a randomized controlled trial and were included in the final analysis. Participants in the HIIT group (n = 18) performed ∼30 min of arm crank exercise (60 s intervals at 80%-90% peak heart rate) four times per week, for 6 weeks. Participants in the control (CON) group (n = 9) were asked to maintain their habitual diet and physical activity patterns over the study period. Outcome measures were taken at baseline and follow-up. The primary outcome measures were fasting insulin, peak power output (PPO) and peak aerobic capacity (V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ ). Secondary outcome measures included body composition, postprandial glycaemic control, fasting blood lipids, inflammatory biomarkers and resting blood pressure. Differences between groups were assessed by ANCOVA, using baseline values as a covariate. PPO was higher in the HIIT (101 W, 97-106) compared to the CON (90 W, 83-96) group at follow-up (P = 0.006). There were no differences in fasting insulin (P = 0.415) or relativeV ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ (P = 0.417). Postprandial Matsuda insulin sensitivity index (ISIMatsuda) was higher in the HIIT (5.42, 4.69-6.15) compared to the CON (3.75, 2.46-5.04) group at follow-up (P = 0.036). Six weeks of upper-body HIIT increased PPO and ISIMatsuda, with no other beneficial effect on cardiometabolic component risks in persons with chronic paraplegia. HIGHLIGHTS: What is the central question of this study? What is the effect of upper-body high intensity interval training (HIIT) on cardiometabolic component risks in individuals with chronic paraplegia? What is the main finding and its importance? Six weeks of upper-body HIIT increased PPO and improved insulin sensitivity, but had no beneficial effect on other cardiometabolic component risks in persons with chronic paraplegia. The large effect size observed for insulin sensitivity may be important in terms of reducing the risk of type-2 diabetes in this population.

Investigating the Alcohol Effects on the Response to Strenuous Exercise Training: Protocol for a Multidisciplinary Intervention Study in Young Healthy Adults-The BEER-HIIT Study

High-intensity interval training (HIIT) is a time-efficient strategy to improve fitness and performance. Whereas the multiple and negative effects of high intake of alcohol have been widely studied, the effect of moderate alcohol doses after exercise is not clear, and it is currently under debate. For that, a total of 80 young healthy adults are studied and allocated into 5 groups, each including 16 participants. Four groups follow a HIIT program, while the fifth group is a control non-training group. The training groups will be randomized according to the characteristics of the ingested beverage (alcohol beer, beer 0.0%, sparkling water, or ethanol). The effects of HIIT on several aspects of physical performance and mental health in young healthy adults are evaluated, also the concomitant effect of daily and moderate alcohol consumption. The novelty of this study lies in the continuous measurement of the psychological parameters associated with carrying out a highly demanding training program in conjunction with alcohol consumption in moderate quantities, reflecting real-life conditions.

Effect of high-intensity interval training vs. moderate-intensity continuous training on cardiometabolic risk factors in overweight and obese individuals

OBJECTIVES

Our study aims to compare the effects of an 8-week high-intensity interval training (HIIT) vs. moderate-intensity continuous training (MICT) on cardiometabolic risk factors and on serum leptin levels in overweight and obese individuals.

METHODS

Our quasi-experimental study involved 36 students who were assigned to HIIT, MICT or the control group. Using a bicycle ergometer, participants in the HIIT group performed 25 min of HIIT and those in the MICT group performed 35 min of moderate-intensity continuous exercise for three days a week for 8 weeks. Body composition estimated by bioimpedance analysis, blood lipids and serum leptin were measured pre-exercise and 8 weeks post-exercise.

RESULTS

After 8 weeks of exercise, the participants in the MICT group showed a significant reduction in weight (p<0.01) and body mass index (BMI) (p<0.05). In the HIIT group, although weight reduction was noticed, the difference was not statistically significant compared to the pre-exercise values. In the control group, participants had a significant increase in their weight, BMI, and total body fat (p<0.05). On performing an inter-group comparison of the magnitude of change in body weight and BMI over 8 weeks of exercise, no difference was seen between the HIIT and MICT groups. No difference was observed in body fat indices and levels of random blood glucose, blood lipids and serum leptin pre and 8 weeks post-exercise.

CONCLUSIONS

On comparing the change in body weight and BMI over 8 weeks, no significant difference was found between the HIIT and MICT groups. However, HIIT was notably more time efficient.

Impact of Fruit and Vegetable Enzyme Supplementation on Aerobic Performance and Lactate Response in Older Adults Following High-Intensity Interval Exercise Through Exergaming: Randomized Experimental Matched-Pair Study

Background

Exercise offers substantial health benefits but can induce oxidative stress and inflammation, especially in high-intensity formats such as high-intensity interval exercise (HIIE). Exergaming has become an effective, enjoyable fitness tool for all ages, particularly older adults. Enzyme supplements may enhance exercise performance by improving lactate metabolism and reducing oxidative stress.

Objective

This study investigates the efficacy of fruit and vegetable enzyme supplementation in modulating fatigue and enhancing aerobic capacity in older adults following HIIE through exergaming.

Methods

The study recruited 16 older adult female participants and allocated them into 2 distinct groups (enzyme and placebo) based on their pretest lactate levels. This division used pairwise grouping to guarantee comparability between the groups, ensuring the integrity of the results. They engaged in HIIE using Nintendo Switch Ring Fit Adventure, performing 8 sets of 20 seconds of maximum effort exercise interspersed with 30 seconds of rest, totaling 370 seconds of exercise. Key metrics assessed included blood lactate levels, heart rate, rating of perceived exertion, and training impulse. Participants in the enzyme group were administered a fruit and vegetable enzyme supplement at a dosage of 30 mL twice daily over a period of 14 days.

Results

The enzyme group showed significantly lower blood lactate levels compared to the placebo group, notably after the fourth (mean 4.29, SD 0.67 vs mean 6.34, SD 1.17 mmol/L; P=.001) and eighth (mean 5.84, SD 0.63 vs mean 8.20, SD 1.15 mmol/L; P<.001) exercise sessions. This trend continued at 5 minutes (mean 6.85, SD 0.82 vs mean 8.60, SD 1.13 mmol/L; P=.003) and 10 minutes (mean 5.91, SD 1.16 vs mean 8.21, SD 1.27 mmol/L; P=.002) after exercise. Although both groups exceeded 85% of their estimated maximum heart rate during the exercise, enzyme supplementation did not markedly affect the perceived intensity or effort.

Conclusions

The study indicates that fruit and vegetable enzyme supplementation can significantly reduce blood lactate levels in older adults following HIIE through exergaming. This suggests a potential role for these enzymes in modulating lactate production or clearance during and after high-intensity exercise. These findings have implications for developing targeted interventions to enhance exercise tolerance and recovery in older adults.

Post Stroke Exercise Training: Intensity, Dosage, and Timing of Therapy

More intense, earlier exercise in rehabilitation results in improved motor outcomes following stroke. Timing and intensity of therapy delivery vary from study to study. For more intensive therapies, there are practical challenges in implementation. However, there are also opportunities for high intensity treatment through innovative approaches and new technologies. Timing of rehabilitation is important. As time post stroke increases, the dosage of therapy required to improve motor recovery outcomes increases. Very early rehabilitation may improve motor outcomes but should be delayed for at least 24 hours post stroke.

Short-Term High-Intensity Rowing Ergometry Training Improves Rowing Performance Equally in Healthy Weight and Obese Adolescents

PURPOSE

Childhood obesity is a major health concern and physical activity is commonly proposed as an intervention strategy to combat the increasing prevalence of overweight and obesity in young people. The aim of this study was to examine the effect of high-intensity, supervised, rowing ergometer training on maximal and submaximal rowing performance in healthy weight and centrally obese adolescents (12-13 yr).

METHODS

Participants were randomized to either 6 wk of supervised rowing ergometry, comprising of 2 sessions per week with each session comprising of 2 × 3-min bouts of high-intensity rowing ergometry ( n = 57), or a control group who continued with their habitual activities ( n = 45). At baseline and follow-up, rowing performance was assessed via a submaximal test and a 3-min maximal test.

RESULTS

Six weeks of rowing ergometer training significantly improved maximal exercise performance; total distance rowed in a 3-min maximal effort improved by 19.7 m (2.7%) (time × group, P = 0.018) and produced a significant reduction in perceived effort in response to a set submaximal load (60 W) (time × group, P = 0.040). At baseline total distance rowed during the 3-min maximal test was significantly affected by body mass (main effect of body mass, P = 0.002), whereby a higher body mass was associated with enhanced rowing performance. However, the pattern of change over time was not different between healthy weight and centrally obese adolescents (time × group × waist centile, P = 0.577).

CONCLUSIONS

A 6-wk high-intensity rowing ergometry training intervention improved maximal rowing performance. This improvement was similar in healthy weight versus overweight and obese adolescents; yet overall overweight and obese adolescents had superior rowing performance compared to their healthy weight counterparts, suggesting that rowing may be an attractive exercise modality for interventions in overweight and obese young people.

Acute physiological and psychological responses during an incremental treadmill test wearing a new upper-body sports garment with elastomeric technology

Background: The use of elastomeric technology in sports garments is increasing in popularity; however, its specific impact on physiological and psychological variables is not fully understood. Thus, we aimed to analyze the physiological (muscle activation of the pectoralis major, triceps brachii, anterior deltoid, and rectus abdominis, capillary blood lactate, systolic and diastolic blood pressure, and heart rate) and psychological (global and respiratory rating of perceived exertion [RPE]) responses during an incremental treadmill test wearing a new sports garment for the upper body that incorporates elastomeric technology or a placebo garment. Methods: Eighteen physically active young adults participated in two randomized sessions, one wearing the elastomeric garment and the other wearing a placebo. Participants performed in both sessions the same treadmill incremental test (i.e., starting at 8 km/h, an increase of 2 km/h each stage, stage duration of 3 min, and inclination of 1%; the test ended after completing the 18 km/h Stage or participant volitional exhaustion). The dependent variables were assessed before, during, and/or after the test. Nonparametric tests evaluated differences. Results: The elastomeric garment led to a greater muscle activation (p < 0.05) in the pectoralis major at 16 km/h (+33.35%, p = 0.01, d = 0.47) and 18 km/h (+32.09%, p = 0.02, d = 0.55) and in the triceps brachii at 10 km/h (+20.28%, p = 0.01, d = 0.41) and 12 km/h (+34.95%, p = 0.04, d = 0.28). Additionally, lower lactate was observed at the end of the test (-7.81%, p = 0.01, d = 0.68) and after 5 min of recovery (-13.71%, p < 0.001, d = 1.00) with the elastomeric garment. Nonsignificant differences between the garments were encountered in the time to exhaustion, cardiovascular responses, or ratings of perceived exertion. Conclusion: These findings suggest that elastomeric garments enhance physiological responses (muscle activation and blood lactate) during an incremental treadmill test without impairing physical performance or effort perception.

Exploring the Design of Upper Limb Strength Training Through High-Intensity Interval Training Combined With Exergaming: Usability Study

Background

High-intensity interval training (HIIT) has become a popular exercise strategy in modern society, with the Tabata training method being the most popular. In the past, these training methods were mostly done without equipment, but incorporating exergaming into the training may provide a new option for muscle training.

objectives

The aim of this study was to explore the differences in upper limb muscle activation using an HIIT program combined with exergaming.

Methods

A total of 15 healthy male participants were recruited for the study, and the differences in muscle activation were compared between push-ups and exergaming (Nintendo Switch Ring Fit Adventure with the Ring-Con accessory) during HIIT. Prior to the tests, participants underwent pretests, including maximal voluntary contractions of various muscle groups, maximal push-up tests, and maximal movement tests using the exergaming device. The push-up and exergaming tests were conducted on separate days to avoid interference, with a warm-up period of 5 minutes on a treadmill before testing. Muscle activation in the lateral and anterior portions of the deltoid muscle, the sternal and clavicular heads of the pectoralis major muscle, and the latissimus dorsi muscle were measured during the maximal voluntary contractions and single-round tests for each exercise mode. A repeated measures ANOVA was used to assess the variations in muscle activation observed across the 2 distinct modes of exercise, specifically push-ups and exergaming.

Results

In exergaming, the number of repetitions for push-ups was significantly fewer than for single-site exercises across both exhaustive (mean 23.13, SD 6.36 vs mean 55.67, SD 17.83; P=.001; effect size [ES]: 2.43) and single-round (mean 21.93, SD 7.67 vs mean 92.40, SD 20.47; P=.001; ES: 4.56) training. Heart rate differences were not significant (all P>.05), yet exergaming led to better muscle activation in specific muscle groups, particularly the right anterior deltoid (mean 48.00%, SD 7.66% vs mean 32.84%, SD 10.27%; P=.001; ES: 1.67) and right pectoralis major (sternal head: mean 38.99%, SD 9.98% vs mean 26.90%, SD 12.97%; P=.001; ES: 1.04; clavicular head: mean 43.54%, SD 9.59% vs mean 30.09%, SD 11.59%; P=.002; ES: 1.26) during exhaustive training. In single-round training, similar patterns were observed with the anterior deltoid (mean 51.37%, SD 11.76% vs mean 35.47%, SD 12.72%; P=.002; ES: 1.30) and pectoralis major (sternal head: mean 53.27%, SD 10.79% vs mean 31.56%, SD 16.92%; P=.001; ES: 1.53; clavicular head: mean 53.75%, SD 13.01% vs mean 37.95%, SD 14.67%; P=.006; ES: 1.14). These results suggest that exergaming may be more effective for targeted muscle activation.

Conclusions

In conclusion, HIIT can increase muscle activation in the upper extremities and can be incorporated into exergaming strategies to provide a fun and engaging way to exercise.

The enhancement of explosive power contributes to the development of anaerobic capacity: A comparison of autoregulatory progressive resistance exercise and velocity-based resistance training

Objectives

Due to the character of the taekwondo, the adenosine triphosphate-phosphocreatine system provides the energy for each kick, the glycolytic system supports the repeated execution of kicks, and the aerobic system promotes recovery between these movements and the bout. Therefore, taekwondo athletes require high explosive power and anaerobic capacity in order to carry out sustained and powerful attacks. So, the purpose of this study is to compare the effects of APRE and VBRT on lower-limb explosive power and anaerobic capacity in college taekwondo players.

Methods

A total of 30 taekwondo players completed an 8-week training intervention with autoregulatory progressive resistance exercise (APRE; n = 15) and velocity-based resistance training (VBRT; n = 15). Testing included the one-repetition maximum squat, countermovement jump (CMJ), taekwondo anaerobic intermittent kick test (TAIKT), and 30-s Wingate anaerobic test (WAnT).

Results

(1) Intragroup comparisons revealed significant effects for one-repetition maximum squat, peak power of CMJ (CMJPP), relative peak power of CMJ (CMJRPP), and total number of TAIKT (TAIKTTN) in both the APRE and VBRT groups. The VBRT group exhibited small effect sizes for time at peak power of WAnT (WAnTPPT) and moderate effect sizes for peak power of WAnT (WAnTPP), relative peak power of WAnT (WAnTRPP), and fatigue index of TAIKT (TAIKTFI), whereas the APRE group exhibited small effect sizes for TAIKTFI. (2) Intergroup comparisons revealed no significant effects in any of the results. However, VBRT demonstrated a moderate advantage in WAnTPP and WAnTRPP, whereas APRE had a small advantage in CMJPP and CMJRPP.

Conclusions

These findings suggest that APRE improved explosive power (CMJPP and CMJRPP) more, whereas VBRT improved anaerobic power output (WAnTPP and WAnTRPP) more. Both methods were found to have similar effects in improving the anaerobic endurance (WAnTPPT and TAIKTTN) and fatigue index (power drop of WAnT and TAIKTFI).

The impact of sprint interval training versus moderate intensity continuous training on blood pressure and cardiorespiratory health in adults: a systematic review and meta-analysis

Background

Although aerobic exercise is the primary modality recommended for the treatment of hypertension, it remains unclear whether high-intensity all-out sprint interval training (SIT) can result in greater reductions of blood pressure (BP) and cardiorespiratory health. This systematic review aims to compare the impact of SIT versus Moderate-intensity continuous training (MICT) on improvements in resting systolic blood pressure (SBP), diastolic blood pressure (DBP) and maximal oxygen uptake (VO2 max) among adults.

Methods

We conducted a systematic search of three online databases (PubMed, Embase, and Web of Science) from January 2000 to July 2023 to identify randomized controlled trials that compared the chronic effects of SIT versus MICT on BP in participants with high or normal blood pressure. We extracted information on participant characteristics, exercise protocols, BP outcomes, and intervention settings. Furthermore, the changes in VO2 max between the two groups were analyzed using a meta-analysis. The pooled results were presented as weighted means with 95% confidence intervals (CI).

Results

Out of the 1,874 studies initially were found, eight were included in this review, totaling 169 participants. A significant decrease in SBP (MD = -2.82 mmHg, 95% CI [-4.53 to -1.10], p = 0.08, I2 =45%) was observed in the SIT group compared to before the training, but no significant decrease in DBP (MD = -0.75 mmHg, 95% CI [-1.92 to 0.42], p = 0.16, I2 = 33%) was observed. In contrast, both SBP (MD = -3.00 mmHg, 95% CI [-5.31 to -0.69], p = 0.68, I2 = 0%) and DBP (MD = -2.11 mmHg, 95% CI [-3.63 to -0.60], p = 0.72, I2 = 0%) significantly decreased in the MICT group with low heterogeneity. No significant difference was found in resting SBP and DBP between SIT and MICT after the intervention. Both SIT and MICT significantly increased VO2 peak, with SIT resulting in a mean difference (MD) of 1.75 mL/kg/min (95% CI [0.39-3.10], p = 0.02, I2 = 61%), and MICT resulting in a mean difference of 3.10 mL/kg/min (95% CI [1.03-5.18], p = 0.007, I2 = 69%). MICT was more effective in improving VO2 peak (MD = -1.36 mL/kg/min, 95% CI [-2.31 to 0.40], p = 0.56, I2 = 0%). Subgroup analysis of duration and single sprint time showed that SIT was more effective in reducing SBP when the duration was ≥8 weeks or when the sprint time was <30 s.

Conclusion

Our meta-analysis showed that SIT is an effective intervention in reducing BP and improving cardiorespiratory fitness among adults. Consequently, SIT can be used in combination with traditional MICT to increase the variety, utility, and time efficiency of exercise prescriptions for different populations.

Is low-volume high-intensity interval training a time-efficient strategy to improve cardiometabolic health and body composition? A meta-analysis

The present meta-analysis aimed to assess the effects of low-volume high-intensity interval training (LV-HIIT; i.e., ≤5 min high-intensity exercise within a ≤15 min session) on cardiometabolic health and body composition. A systematic search was performed in accordance with PRISMA guidelines to assess the effect of LV-HIIT on cardiometabolic health and body composition. Twenty-one studies (moderate to high quality) with a total of 849 participants were included in this meta-analysis. LV-HIIT increased cardiorespiratory fitness (CRF, SMD = 1.19 [0.87, 1.50]) while lowering systolic blood pressure (SMD = -1.44 [-1.68, -1.20]), diastolic blood pressure (SMD = -1.51 [-1.75, -1.27]), mean arterial pressure (SMD = -1.55 [-1.80, -1.30]), MetS z-score (SMD = -0.76 [-1.02, -0.49]), fat mass (kg) (SMD = -0.22 [-0.44, 0.00]), fat mass (%) (SMD = -0.22 [-0.41, -0.02]), and waist circumference (SMD = -0.53 [-0.75, -0.31]) compared to untrained control (CONTROL). Despite a total time-commitment of LV-HIIT of only 14%-47% and 45%-94% compared to moderate-intensity continuous training and HV-HIIT, respectively, there were no statistically significant differences observed for any outcomes in comparisons between LV-HIIT and moderate-intensity continuous training (MICT) or high-volume HIIT. Significant inverse dose-responses were observed between the change in CRF with LV-HIIT and sprint repetitions (β = -0.52 [-0.76, -0.28]), high-intensity duration (β = -0.21 [-0.39, -0.02]), and total duration (β = -0.19 [-0.36, -0.02]), while higher intensity significantly improved CRF gains. LV-HIIT can improve cardiometabolic health and body composition and represent a time-efficient alternative to MICT and HV-HIIT. Performing LV-HIIT at a higher intensity drives higher CRF gains. More repetitions, longer time at high intensity, and total session duration did not augment gains in CRF.

Effects of Physical Exercise on Telomere Length in Healthy Adults: Systematic Review, Meta-Analysis, and Meta-Regression

BACKGROUND

Physical exercise is one of the main nonpharmacological treatments for most pathologies. In addition, physical exercise is beneficial in the prevention of various diseases. The impact of physical exercise has been widely studied; however, existing meta-analyses have included diverse and heterogeneous samples. Therefore, to our knowledge, this is the first meta-analysis to evaluate the impact of different physical exercise modalities on telomere length in healthy populations.

OBJECTIVE

In this review, we aimed to determine the effect of physical exercise on telomere length in a healthy population through a meta-analysis of randomized controlled trials.

METHODS

A systematic review with meta-analysis and meta-regression of the published literature on the impact of physical exercise on telomere length in a healthy population was performed. PubMed, Cochrane Library, SCOPUS, Web of Science, and Embase databases were searched for eligible studies. Methodological quality was evaluated using the Risk Of Bias In Nonrandomized Studies of Interventions and the risk-of-bias tool for randomized trials. Finally, the certainty of our findings (closeness of the estimated effect to the true effect) was evaluated using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE).

RESULTS

We included 9 trials that met the inclusion criteria with fair methodological quality. Random-effects model analysis was used to quantify the difference in telomere length between the exercise and sham groups. Meta-analysis showed that exercise did not significantly increase telomere length compared with the control intervention (mean difference=0.0058, 95% CI -0.05 to 0.06; P=.83). Subgroup analysis suggested that high-intensity interventional exercise significantly increased telomere length compared with the control intervention in healthy individuals (mean difference=0.15, 95% CI 0.03-0.26; P=.01). Furthermore, 56% of the studies had a high risk of bias. Certainty was graded from low to very low for most of the outcomes.

CONCLUSIONS

The findings of this systematic review and meta-analysis suggest that high-intensity interval training seems to have a positive effect on telomere length compared with other types of exercise such as resistance training or aerobic exercise in a healthy population.

TRIAL REGISTRATION

PROSPERO CRD42022364518; http://tinyurl.com/4fwb85ff.

Cardiorespiratory Fitness and Performance Adaptations to High-Intensity Interval Training: Are There Differences Between Men and Women? A Systematic Review with Meta-Analyses

BACKGROUND

It is important to consider biological sex as a variable that might influence exercise adaptation in order to optimize exercise prescription for men and women.

OBJECTIVE

The aim of this study was to quantify the impact of biological sex on maximal oxygen uptake ([Formula: see text]O2max) and performance outcomes after high-intensity interval training (HIIT).

METHODS

A systematic search and review was conducted by two independent reviewers up to 8 September 2022 using MEDLINE, SPORTDiscus, and Sports Medicine & Education Index in ProQuest. Trials including healthy adults were included if they presented data for or compared male and female [Formula: see text]O2max or performance outcomes in response to HIIT. Performance outcomes included measures of exercise performance and concurrently measured physiological adaptations. Where appropriate, a random-effects, pre-post meta-analysis was undertaken. Data were sub-grouped for men and women, baseline training level, mean age, intervention type, and intervention length. Heterogeneity was assessed using Chi2, Cochran's Q, and Higgins I2 and sensitivity analyses, where required. Study quality was assessed using the Newcastle-Ottawa Scale and publication bias was assessed through visual inspection of funnel plots.

RESULTS

Thirty-three references from 28 trials were included in the review (n = 965; 462 women and 503 men). Meta-analyses included 19 studies for [Formula: see text]O2max, eight for peak power output from [Formula: see text]O2max testing (PPO), and five for threshold power (powerAT). Meta-analyses revealed similar increases in [Formula: see text]O2max in women (g = 0.57; 95% CI 0.44-0.69) and men (g = 0.57; 95% CI 0.42-0.72), and powerAT in women (g = 0.38; 95% CI 0.13-0.64) and men (g = 0.38; 95% CI 0.11-0.64). Raw mean differences for change in [Formula: see text]O2max were Δ 0.32 L·min-1 and 3.50 mL·kg-1·min-1 in men, versus Δ 0.20 L·min-1 and 3.34 mL·kg-1·min-1 for women. No significant sex differences were present for the primary analysis of any outcome. After sub-grouping, significant differences were present for PPO where the effect size was higher for well-trained women (g = 0.37) compared with well-trained men (g = 0.17), and for [Formula: see text]O2max where interventions with a duration of 4 weeks or less had significantly smaller effect sizes compared with those longer than 4 weeks (p < 0.001). Unweighted mean percentage change in [Formula: see text]O2max, PPO, and powerAT across studies was 11.16 ± 7.39%, 11.16 ± 5.99%, and 8.07 ± 6.55% for women, and 10.90 ± 5.75%, 8.22 ± 5.09%, and 7.09 ± 7.17% for men, respectively. Significant heterogeneity was present for both [Formula: see text]O2max and PPO (I2, range: 62.06-78.80%). Sub-grouping by baseline training status and intervention length decreased heterogeneity in most groups. A qualitative synthesis of other outcomes indicated similar improvements in fitness and performance for men and women with some evidence suggesting differences in the mechanisms of adaptation.

LIMITATIONS AND RISK OF BIAS

Publication bias is unlikely to have significantly influenced results for [Formula: see text]O2max or powerAT, but the meta-analysis of PPO could have benefitted from additional study data to strengthen results. The overlap in age categories and sensitivity of the analysis limits the accuracy of the results of the sub-grouping by age.

CONCLUSIONS

Findings indicated no sex-specific differences for any fitness or performance outcomes. Baseline training status and intervention length accounted for most variability in outcomes. PROSPERO registration number: CRD42021272615.

Effects of high-intensity interval training on retinal vessel diameters and oxygen saturation in patients with hypertension: A cross-sectional and randomized controlled trial

INTRODUCTION

Arterial hypertension is a global healthcare burden that affects macrovascular and microvascular structure and function and can promote vascular end-organ damage. This study aimed 1) to evaluate differences in microvascular health between normotensive individuals and patients with arterial hypertension and 2) to assess the effects of short-term high-intensity interval training (HIIT) on microvascular health in the subgroup with arterial hypertension as add-on treatment to antihypertensive medication.

METHODS

In the cross-sectional part, central retinal arteriolar (CRAE) and venular diameter equivalent (CRVE), arteriolar-to-venular diameter ratio (AVR), and retinal oxygen saturation (O2-saturation) were investigated in 19 normotensive healthy controls (mean age 56 ± 7 years) and 41 patients with arterial hypertension (mean age 59 ± 7 years). In the subsequent randomized controlled trial (RCT), patients with arterial hypertension were randomized to an intervention group (HIIT 3×/week) or a control group that received standard physical activity recommendations after baseline assessment. Assessments of retinal vessel biomarkers and patients` characteristics were repeated after the intervention period of 8 weeks.

RESULTS

In the cross-sectional part, individuals with normal blood pressure (BP) showed lower body mass index (BMI), body fat, 24 h systolic and diastolic BP, higher peak oxygen uptake, wider CRAE (174 ± 17 μm vs. 161 ± 17 μm, p = 0.009), and higher AVR (0.84 ± 0.05 vs. 0.79 ± 0.05, p = 0.003) compared to patients with hypertension. In the RCT, patients with arterial hypertension showed reduced BMI and fasting glucose levels after HIIT and control condition. In addition, the intervention group reduced body fat percentage (27.0 ± 5.5 vs. 25.8 ± 6.1, p = 0.023) and increased peak oxygen uptake (33.3 ± 5.7 vs. 36.7 ± 5.1, p < 0.001). No changes in BP were found in either group. The intervention group showed narrower CRVE (β -4.8 [95 % CI, -8.85, -0.81] p = 0.020) and higher AVR (0.03 [0.01, 0.04] p < 0.001) after eight weeks of HIIT compared to the control group. No statistically significant changes in retinal O2-saturation were found in either group.

CONCLUSION

Short-term HIIT proved to be an effective treatment to ameliorate hypertension-induced retinal microvascular abnormalities in patients with hypertension. Retinal vessel diameters may prove to be a sensitive biomarker to quantify treatment efficacy at the microvascular level, at the earliest possible stage in patients with hypertension.

Feedback control of heart rate during treadmill exercise based on a two-phase response model

This work investigated automatic control of heart rate during treadmill exercise. The aim was to theoretically derive a generic feedback design strategy that achieves a constant input sensitivity function for linear, time-invariant plant models, and to empirically test whether a compensator C2 based on a second-order model is more dynamic and has better tracking accuracy than a compensator C1 based on a first-order model. Twenty-three healthy participants were tested using first and second order compensators, C1 and C2, respectively, during 35-minute bouts of constant heart rate treadmill running. It was found that compensator C2 was significantly more accurate, i.e. it had 7% lower mean root-mean-square tracking error (1.98 vs. 2.13 beats per minute, p = 0.026), and significantly more dynamic, i.e. it had 17% higher mean average control signal power (23.4 × 10-4 m2/s2 vs. 20.0 × 10-4 m2/s2, p = 0.011), than C1. This improvement likely stems from the substantially and significantly better fidelity of second-order models, compared to first order models, in line with classical descriptions of the different phases of the cardiac response to exercise. These outcomes, achieved using a treadmill, are consistent with previous observations for the cycle ergometer exercise modality. In summary, whenever heart rate tracking accuracy is of primary importance and a more dynamic control signal is acceptable, the use of a compensator based on a second-order nominal model is recommended.

Cardiorespiratory fitness and cardiovascular risk among in-patients with depression compared to healthy controls

Introduction

Compared to the general population, individuals with depression have an increased risk for cardiovascular diseases. Nevertheless, little is known so far whether cardiorespiratory fitness (CRF) moderates this relationship. Therefore, we examined whether common physiological cardiovascular risk factors differ between patients with depression and healthy (non-depressed) controls, whether patients and controls differ in CRF, and whether higher CRF is associated with a lower cardiovascular risk in both patients and healthy controls. Additionally, we examined whether within the patient sample, cardiovascular risk factors differ between patients with mild, moderate and severe depression, and whether the relationship between symptom severity and cardiovascular risk is moderated by patients' CRF levels.

Methods

Data from a multi-centric, two-arm randomized controlled trial (RCT) was analyzed, including 210 patients (F32, single episode: n = 72, F33, recurrent major depression: n = 135, F31-II, bipolar type II: n = 3) and 125 healthy controls. Waist circumference, body mass index, body fat, blood pressure, cholesterol levels, triglycerides, and blood glucose were considered as cardiovascular risk markers. CRF was assessed with a submaximal ergometer test. Differences between groups were examined via χ²-tests and (multivariate) analyses of covariance.

Results

Compared to healthy controls, patients with depression had a higher cardiovascular risk as evident from about half of the examined indicators. In the total sample, participants with good CRF had more favourable scores across nearly all risk markers than counterparts with poor CRF. For most variables, no interaction occurred between group and fitness, indicating that in patients and controls, similar differences existed between participants with poor and good CRF. Few differences in risk markers were found between patients with mild, moderate and severe depression, and no interaction occurred between depression severity and CRF.

Discussion

Patients with depression and healthy controls differ in several cardiovascular risk markers, putting patients at increased risk for CVDs. In contrast, people with good CRF show more favourable cardiovascular risk scores, a relationship which was observed in both healthy controls and patients with depression. Physical health of psychiatric patients should receive the clinical attention that it deserves. Lifestyle interventions targeting healthy diet and/or physical activity are recommended as a physically active and healthy lifestyle contributes equally to patients' mental well-being and cardiovascular health.

The effects of exercise training on body composition in postmenopausal women: a systematic review and meta-analysis

INTRODUCTION

We conducted a systematic review and meta-analysis to investigate the effect of exercise training on body composition outcomes in postmenopausal women.

METHODS

PubMed, Web of Science, CINAHL, and Medline were searched to identify the randomized controlled trials which evaluated effect of exercise training versus control in postmenopausal women. Standardized mean differences (SMD), weighted mean differences (WMD) and 95% confidence intervals (95% CIs) were calculated using random effects model.

RESULTS

One hundred and one studies involving 5,697 postmenopausal women were included in the meta-analysis. Results indicated that exercise training effectively increased muscle mass/ volume, muscle and fiber cross-sectional area and fat-free mass, and decreased fat mass, body fat percentage, waist circumference and visceral fat. Furthermore, subgroup analyses results revealed that aerobic and combined training had greater beneficial effects on fat mass outcomes, whereas resistance and combined training had greater beneficial effects on muscle mass outcomes.

DISCUSSION

Overall, our results revealed that exercise training is effective for improving body composition in postmenopausal women. To be specific, aerobic training is effective on fat loss, whereas resistance training is effective on muscle gain. However, combination of aerobic and resistance trainings may be considered a viable strategy to improve body composition in postmenopausal women.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD42021283425.

Moderate to Vigorous-intensity Continuous Training versus High-intensity Interval Training for improving VO2max in women: A systematic review and meta-analysis

Traditional continuous training and high-intensity interval training (HIIT) can increase maximal oxygen uptake (V̇O_2max). However, there is conflicting evidence regarding which form of training demonstrates the greatest improvements to V̇O_2max, and data in women is sparse. We conducted a systematic review and meta-analyses to assess whether moderate to vigorous-intensity continuous training (MVICT) or HIIT was superior at improving V̇O_2max in women. Randomised controlled and parallel studies examined the influence of MVICT and/or HIIT on V̇O_2max in women. There was no statistical difference in V̇O_2max improvements after training between women in the MVICT and HIIT cohorts (mean difference [MD]: -0.42, 95%CI: -1.43 to 0.60, p>0.05). Both MVICT and HIIT increased V̇O_2max from baseline (MD: 3.20, 95% CI: 2.73 to 3.67 and MD: 3.16, 95% CI 2.09 to 4.24, respectively, p<0.001). Greater improvements in V̇O_2max were observed in women who participated in more training sessions in both training formats. Long-HIIT was superior to short-HIIT protocols at increasing V̇O_2max. Although MVICT and long-HIIT sessions elicited greater increases in V̇O_2max in younger women compared to short-HIIT protocols, these differences were negligible in older women. Our findings suggest MVICT and HIIT are equally effective strategies for improving V̇O_2max and indicate an effect of age on its response to training in women.

Microvascular wall-to-lumen ratio in patients with arterial hypertension: A randomized controlled exercise trial

BACKGROUND AND AIMS

High blood pressure is one of the main cardiovascular disease risk factors that contribute to vascular remodeling and dysfunction. We aimed to investigate I) group differences of the retinal microstructure between patients with hypertension and healthy individuals and II) the effects of a high-intensity interval training (HIIT) on hypertension-induced microvascular remodeling in patients with hypertension in a randomized controlled trial.

METHODS

Arteriolar and venular retinal vessel microstructure including retinal vessel wall (RVW), lumen diameter and wall-to-lumen ratio (WLR) of 41 hypertensive patients, treated with anti-hypertensive medication, and 19 normotensive healthy controls were screened based on high-resolution fundoscopies. Patients with hypertension were randomized to a control group receiving standard physical activity recommendations and an intervention group receiving a supervised and walking-based HIIT for eight weeks. Measurements were repeated after the intervention period.

RESULTS

Hypertensive patients showed thicker arteriolar RVW (28.0 ± 7.7mu vs. 21.4 ± 4.4mu, p = 0.003) and higher arteriolar WLR (58.5 ± 14.8 % vs. 42.5 ± 8.2 %, p < 0.001) compared to normotensive controls. The intervention group showed reductions in arteriolar RVW (β -3.1 (95 % CI, -4.38, -1.78) p < 0.001) and arteriolar WLR (-5.3 (-10.14, -0.39) p = 0.035) compared to the control group. The intervention effects were independent of age, sex, change in blood pressure and change in cardiorespiratory fitness.

CONCLUSIONS

HIIT in patients with hypertension improves retinal vessel microvascular remodeling after eight weeks of training. In patients with hypertension, screening retinal vessel microstructure by fundoscopy and monitoring efficacy of short-term exercise treatment are sensitive diagnostic approaches to quantify microvascular health in these patients.

Universal Training Precautions: A Review of Evidence and Recommendations for Prevention of Exercise-Related Injury, Illness, and Death in Warfighters and Athletes

Facing pressure to train for victory, warfighters and athletes encounter numerous health risks that are directly related to their regular physical training. The concept of universal training precautions (UTPs) signifies universal processes designed to prevent unnecessary bodily harm, including injury, illness, and death, during physical training programs. Although no formal guidelines exist for collectively implementing a defined set of UTPs to address a broad scope of exercise-related health risks, recommendations and guidelines have been published relating to preventing sudden death during high school sports and collegiate conditioning sessions. A long list of critical topics must be considered as UTPs, including physical fitness factors, transition-period accommodation, hydration, environmental factors and acclimatization, appropriate recovery, use of medications and dietary supplements, and importantly, leadership. In this article, we outline in detail, with corresponding Strength of Recommendation Taxonomy ratings, what should be considered universal recommendations to minimize the risk of warfighters and athletes coming to harm when participating in group physical activities.

Acute Physiological Responses to Moderate-Intensity Continuous, High-Intensity Interval, and Variable-Intensity Intermittent Exercise

Purpose: This study examined acute physiological responses to moderate-intensity continuous exercise (MICE), variable-intensity intermittent exercise (VIIE), and high-intensity interval exercise (HIIE) protocol, matched for total work output in healthy adults (n = 8, age = 25.1 ± 6.0 yrs). Methods: Three experimental trials were completed in a random order. MICE was continuous exercise at 40% of peak work rate (WR_peak). VIIE consisted of sixteen 10-sec bursts at 120% WRpeak, sixteen 20-sec bursts at 60% WR_peak and recovery at 20% WR_peak interspersed throughout the protocol. HIIE consisted of eight intervals of 2 minutes at 70% WR_peak and 1 minute at 20% WR_peak. Oxygen consumption during work-intervals and time within moderate and vigorous-intensity zones determined the magnitude and duration of physiological stresses. Perceptual responses were measured by affective response and post-exercise enjoyment (PACES). Repeated-measure ANOVAs analyzed differences between trials. Statistical significance was established if p ≤ 0.05. Results: Oxygen consumption during work-intervals in VIIE was greater than MICE, but less than HIIE. VIIE and HIIE had similar duration within vigorous-intensity zone (11.1 ± 3.5 min vs. 13.5 ± 1.3 min); both were greater than MICE (4.9 ± 1.1 min). The time spent in the moderate-intensity zone was different between all trials (VIIE = 11.1 ± 2.0 min; MICE = 17.4 ± 5.2 min; HIIE = 4.9 ± 0.4 min). Affective responses were similar among all trials. Post-exercise enjoyment was greater in VIIE than HIIE; both were not different from MICE. Conclusion: These results suggests the VIIE paradigm could be a viable alternative to HIIE and MICE protocols.

With Great Power Comes Great Responsibility: Common Errors in Meta-Analyses and Meta-Regressions in Strength & Conditioning Research

BACKGROUND AND OBJECTIVE

Meta-analysis and meta-regression are often highly cited and may influence practice. Unfortunately, statistical errors in meta-analyses are widespread and can lead to flawed conclusions. The purpose of this article was to review common statistical errors in meta-analyses and to document their frequency in highly cited meta-analyses from strength and conditioning research.

METHODS

We identified five errors in one highly cited meta-regression from strength and conditioning research: implausible outliers; overestimated effect sizes that arise from confusing standard deviation with standard error; failure to account for correlated observations; failure to account for within-study variance; and a focus on within-group rather than between-group results. We then quantified the frequency of these errors in 20 of the most highly cited meta-analyses in the field of strength and conditioning research from the past 20 years.

RESULTS

We found that 85% of the 20 most highly cited meta-analyses in strength and conditioning research contained statistical errors. Almost half (45%) contained at least one effect size that was mistakenly calculated using standard error rather than standard deviation. In several cases, this resulted in obviously wrong effect sizes, for example, effect sizes of 11 or 14 standard deviations. Additionally, 45% failed to account for correlated observations despite including numerous effect sizes from the same study and often from the same group within the same study.

CONCLUSIONS

Statistical errors in meta-analysis and meta-regression are common in strength and conditioning research. We highlight five errors that authors, editors, and readers should check for when preparing or critically reviewing meta-analyses.

Change in Central Cardiovascular Function in Response to Intense Interval Training: A Systematic Review and Meta-analysis

INTRODUCTION

High-intensity interval training and sprint interval training significantly increase maximal oxygen uptake (V̇O 2max ), which enhances endurance performance and health status. Whether this response is due to increases in central cardiovascular function (cardiac output (CO) and blood volume) or peripheral factors is unknown.

PURPOSE

This study aimed to conduct a systematic review and meta-analysis to assess the effects of high-intensity interval training and sprint interval training (referred to as intense interval training) on changes in central cardiovascular function.

METHODS

We performed a systematic search of eight databases for studies denoting increases in V̇O 2max in which CO, stroke volume (SV), blood volume, plasma volume, end-diastolic/systolic volume, or hematocrit were measured.

RESULTS

Forty-five studies were included in this analysis, comprising 946 men and women of various health status (age and V̇O 2max , 20-76 yr and 13-61 mL·kg -1 ·min -1 ) who performed 6-96 sessions of interval training. Results showed an increase in V̇O 2max with intense interval training that was classified as a large effect ( d = 0.83). SV ( d = 0.69), and CO ( d = 0.49) had moderate effect sizes in response to intense interval training. Of 27 studies in which CO was measured, 77% exhibited significant increases in resting CO or that obtained during exercise. Similarly, 93% of studies revealed significant increases in SV in response to intense interval training. Effect sizes for these outcomes were larger for clinical versus healthy populations. Plasma volume, blood volume, and hematocrit had small effect sizes after training ( d = 0.06-0.14).

CONCLUSIONS

Increases in V̇O 2max demonstrated with intense interval training are attendant with increases in central O 2 delivery with little contribution from changes in hematocrit, blood volume, or plasma volume.

Aerobic and Anaerobic Fitness according to High-Intensity Interval Training Frequency in Youth Soccer Players in the Last Stage of Rehabilitation

In the last stage of rehabilitation, high-intensity interval training (HIIT) for improving physical fitness is appropriate for return-to-play; however, some youth athletes visit the rehabilitation center less frequently due to conflict with their distance to center, and academic schedule. We tested the effects of short-term low-frequency HIIT in 54 youth male soccer players, after dividing them into a low-frequency group (LFG, n = 27 players) and a high-frequency group (HFG, n = 27 players). Muscle mass and body fat were measured using a body composition test, and VO₂peak and exercise duration were measured using a treadmill. Five sets of anaerobic peak power and fatigue were measured repeatedly using the Wingate test. To evaluate knee joint muscle function, 60°/s, 180°/s, and 240°/s were measured using the isokinetic muscle function equipment. HIIT sessions were conducted twice a week for LFG and five times a week for HFG for 4 weeks. In this study, Wilcoxon signed-rank test and Mann-Whitney U test were mainly used for analysis. Significant improvements in VO₂peak, anaerobic peak power, and knee strength were observed after intervention in both groups (p < 0.05). In the post test, there were significant differences between groups in VO₂peak (LFG, 56.4 vs. HFG, 57.1 mL/kg/min; p = 0.035), exercise duration (LFG, 972.3 vs. HFG, 990.4 s; p = 0.041), Wingate anaerobic peak power 5 sets (LFG, 606.3 vs. HFG, 629.3 Watt; p = 0.039), and muscle function test 240°/s (LFG, 68.5 vs. HFG, 70.2 Jouls; p = 0.010). However, neither group showed significant changes in body composition, such as muscle mass or body fat (p > 0.05). In conclusion, although it is a short-term training, the effect of HIIT was shown in the HFG as well as LFG. Although HFG improved physical fitness, significant improvement was also achieved in LFG. Therefore, in the last stage of rehabilitation, low frequency as well as high frequency HIIT would be an appropriate training method to improve physical fitness for youth soccer players.

The impact of high-intensity interval training on vascular function in adults: A systematic review and meta-analysis

Aim

We performed a systematic review and meta-analysis to investigate the effects of high-intensity interval training (HIIT) compared with moderate-intensity continuous training (MICT) or with no exercise (CON) on vascular function in adults who were free of cardiometabolic diseases and those with cardiometabolic diseases.

Methods

A search across three electronic databases including Scopus, PubMed, and Web of Science was conducted through February 2022 to identify the randomized trials evaluating HIIT vs. MICT and/or CON on vascular function as measured using brachial artery flow-mediated dilation (FMD) in adults. Separate analyses were conducted for HIIT vs. MICT and/or CON to calculate weighted mean differences (WMD) and 95% confidence intervals (95% CIs) using random or fixed models.

Results

A total of 36 studies involving 1,437 participants who were either free of cardiometabolic diseases or had cardiometabolic diseases were included in the meta-analysis. HIIT effectively increased FMD when compared with MICT [1.59% (95% CI 0.87-2.31), p = 0.001] or CON [3.80% (95% CI 2.58-5.01), p = 0.001]. Subgroup analysis showed that HIIT increased FMD in participants with cardiovascular and metabolic diseases, but not in participants who were free of cardiometabolic diseases. In addition, HIIT effectively increased FMD regardless of age and body mass index.

Conclusion

We confirm that HIIT is effective for improving vascular function in individuals with metabolic disorders and cardiovascular diseases and has a superior effect compared to MICT, demonstrating time efficiency.

Systematic review registration

[https://www.crd.york.ac.uk/prospero], identifier [CRD42022320863].

Experiencing good results promotes positive feelings to high-intensity exercise among young adults: A qualitative study

Introduction

From a public health perspective, it is important to gain more insight into how people can be motivated to maintain effective exercise routines. It is a common belief that moderate-intensity exercise is more pleasant and enjoyable than high-intensity training. This study aims to provide insight into (1) participants' expectations and preferences for training intensity prior to training, (2) how longer-term participation affect participants' experience of endurance training with continuous moderate-intensity training and high-intensity interval training.

Materials and methods

A total of 22 participants (14 women and eight men) between the ages of 21–30 volunteered for participation. Participants were randomized and divided into two equal groups. A total of 17 participants, nine women and eight men, completed the study. One group did moderate-intensity longer-lasting training and the other did high-intensity interval training. All participants completed three training sessions per week for 8 weeks. Semi-structured interviews were conducted with each participant before and after completing the training intervention. Data was analyzed using thematic analysis. This study is a part of a larger study evaluating and comparing the effects on endurance capacity of high-intensity interval training and moderate-intensity training. Physiological data are previously published.

Results

The results describe participants expectations prior to training, and how they experienced the actual training. The overall experience of training comprises several factors that work together. Both expectations and actual experiences (e.g., of physical pleasantness or unpleasantness, of positive or negative emotions, and of actual results from the training) contribute to the participants' overall experience of exercise.

Conclusion

The major finding is that improved physical fitness was a stronger motivator than feelings of pleasantness. Experiencing good results seemed to downplay feelings of unpleasantness and reinforce positive feelings toward exercise. Lack of results reinforce negative feelings toward exercise. Participants reported high-intensity exercise as more unpleasant and exhaustive, but the interval training group were more satisfied and experienced the training as more motivating.

Dementia Prevention in Clinical Practice

Over 55 million people globally are living with dementia and, by 2050, this number is projected to increase to 131 million. This poses immeasurable challenges for patients and their families and a significant threat to domestic and global economies. Given this public health crisis and disappointing results from disease-modifying trials, there has been a recent shift in focus toward primary and secondary prevention strategies. Approximately 40% of Alzheimer's disease (AD) cases, which is the most common form of dementia, may be prevented or at least delayed. Success of risk reduction studies through addressing modifiable risk factors, in addition to the failure of most drug trials, lends support for personalized multidomain interventions rather than a "one-size-fits-all" approach. Evolving evidence supports early intervention in at-risk patients using individualized interventions directed at modifiable risk factors. Comprehensive risk stratification can be informed by emerging principals of precision medicine, and include expanded clinical and family history, anthropometric measurements, blood biomarkers, neurocognitive evaluation, and genetic information. Risk stratification is key in differentiating subtypes of dementia and identifies targetable areas for intervention. This article reviews a clinical approach toward dementia risk stratification and evidence-based prevention strategies, with a primary focus on AD.

Investigating Affective Responses to Remotely Delivered "At Home" Low Volume High Intensity Interval Exercise: A Non-Randomized Parallel Group Feasibility Study

Background

Low volume-high intensity interval exercise (LV-HIIE) has gained interest, due to its efficiency in invoking health and fitness benefits. However, little research has studied "at home" feasibility or effects of LV-HIIE. This study aimed to demonstrate that remote "at-home" LV-HIIE research is possible and to investigate if affective responses to the LV-HIIE protocol, subsequent intentions, and self-efficacy to repeat were related to self-reported tolerance of the intensity of exercise.

Methods

Using self-reported tolerance of the intensity of exercise, 41 healthy, physically active participants (25 female and 16 male; age 21.3 ± 1.0 years, body mass index 23.0 ± 2.9 kg.m2) were divided into low tolerance (LT, n = 14), middle tolerance (MT, n = 15), and high tolerance (HT, n = 12) groups. Participants completed a 20-min LV-HIIE circuit training video [2 × (10 ×30 s work, 15 s rest)] at home. Participants reported ratings of perceived exertion, affective valence, and perceived activation at baseline, during the protocol, immediately post-protocol, and during the cool down. 20-min after completion, respondents answered questions on exercise task self-efficacy and intentions to repeat LV-HIIE.

Results

The study recruited n = 65 individuals, of whom n = 50 passed screening. Ultimately n = 41 (82%) completed the exercise protocol and data collection. Ratings of perceived exertion were not significantly different between groups (p = 0.56), indicating similar perceptions of task difficulty. There was no significant effect of tolerance on affective valence (p = 0.36) or felt arousal (p = 0.06). There was evidence of high individual variability in affective responses within and between participants. Subsequent intentions and self-efficacy to repeat the exercise protocol did not seem to be related to affective valence during or after the protocol.

Discussion

Recruitment and data collection indicated that research into "at home" LV-HIIE is possible. High individual differences in affective responses suggest that LV-HEII may be appropriate for some but not all as an exercise option. Assessing self-reported tolerance of intensity of exercise may not appropriately identify whether or not LV-HIIE will be suitable for an individual.

Design and Validation of a Virtual Physical Education and Sport Science-Related Course: A Learner's Engagement Approach

Learners’ engagement is shown to be a major predictor of learning, performance, and course completion as well as course satisfaction. It is easier to engage learners in a face-to-face teaching and learning format since the teacher can observe and interpret the learner’s facial expression and body language. However, in a virtual setting with the students sitting behind cameras, it is difficult to ascertain engagement as the students might be absent-mindedly attending the class. Henceforth, with the rapid transition to online learning, designing course content that could actively engage the students towards achieving the said elements is, therefore, necessary. We applied a data-driven approach in designing a virtual physical education and sport science−related course via a learner engagement model. A fully online course catering to 132 students that runs for a total of 14 weeks was used as a case study to develop the course. The study was conducted during the 2020/2021 academic year, which was the period of the peak COVID-19 pandemic in Malaysia. The delivery of the course content was implemented in stages to achieve three essential educational outcomes namely, skill and knowledge acquisition, and personal development as well as course satisfaction. We hypothesised that the developed learners’ engagement approach will promote the students’ acquisition of skills and knowledge and foster the personal development of the students through fitness improvement. It is also hypothesised that the students will be satisfied with the course developed upon successful completion. A chi-square analysis projected a statistically significant difference in the skill and knowledge acquisition before and after the programme (p < 0.001). A Wilcoxon rank-sum test demonstrated personal improvement in the overall fitness of the student upon completing the prescribed activity of the course content. Moreover, a total of 96.2%, 95.5% and 93.2% of students expressed their satisfaction with the clarity of the learning objectives, good organisational and course content plan, and appropriate workload of the course designed, respectively. There is sufficient evidence to accept all hypotheses formulated, and hence, we postulated that, since students spend more time outside the classroom, out-of-class learners’ engagement activity should be considered when designing a virtual course to promote lifelong learning, experience, and higher-order thinking. The techniques presented herein could be useful to academics, professionals, and other relevant stakeholders in developing virtual course content within a specific domain of interest.

Hypertension and retinal microvascular dysfunction (HyperVasc): protocol of a randomised controlled exercise trial in patients with hypertension

INTRODUCTION

Hypertension is a global healthcare burden that affects the structure and function of the macrocirculation and microcirculation and induces disease-specific end-organ damage. Vascular biomarkers are essential to timely diagnose this end-organ damage to improve cardiovascular (CV) risk stratification and medical decision making. Exercise therapy is an effective means to improve vascular health and reduce overall CV risk. However, it is still not clear whether high-intensity interval training (HIIT) is recommendable for patients with hypertension to reduce blood pressure, increase cardiorespiratory fitness and ameliorate vascular health.

METHODS AND ANALYSIS

The 'Hypertension and retinal microvascular dysfunction' trial will investigate macrovascular and microvascular impairments in hypertensive patients compared with healthy controls to investigate hypertension-induced end-organ damage by using gold-standard methods as well as newly developed unique retinal microvascular biomarkers. In addition, this trial will investigate the reversibility of retinal end-organ damage by assessing the effects of an 8-week supervised and walking based HIIT on blood pressure, cardiorespiratory fitness as well as macrovascular and microvascular health, compared with a control group following standard physical activity recommendations. Primary outcome will be the arteriolar-to-venular diameter ratio. Secondary outcomes will be arteriolar and venular diameters as well as the flicker-light-induced dilation. Further outcomes will be other retinal microvascular biomarkers, flow-mediated dilation of the brachial artery as well as blood pressure, cardiorespiratory fitness, microalbuminuria, hypertensive retinopathy and classical CV risk markers. Analysis of variance and analysis of covariance will be used to investigate group differences between healthy controls and hypertensive patients and training effects in hypertensive patients, respectively.

ETHICS AND DISSEMINATION

The Ethics Committee of Northwestern and Central Switzerland approved this study (EKNZ-2021-00086). All participants will give informed consent.

TRIAL REGISTRATION NUMBER

NCT04763005.

High-intensity interval training in people with mild multiple sclerosis: a mixed-methods feasibility study

Background/Aims

High-intensity interval training has received increased attention as a mode of exercise, including as a therapy in clinical populations. This study investigated the acceptability of a high-intensity interval training intervention in people with mild multiple sclerosis.

Methods

Participants attended two sessions a week for the 6-week intervention. Each session consisted of 6–10 sets of 60-second high-intensity intervals interspersed with 120 seconds of recovery. The acceptability, intervention adherence and safety of the high-intensity interval training protocol and estimates of treatment effects (fitness, physical activity levels, fatigue and quality of life) were used to determine intervention feasibility. Qualitative interviews were used to explore the acceptability of the intervention.

Results

A total of 11 people with mild multiple sclerosis consented to participate in a 6-week high-intensity interval intervention. One participant dropped out of the intervention. The participants expressed apprehension before the intervention but attendance at the exercise sessions was high (87%). Participants experienced some symptom exacerbation following sessions, although none were serious. Improvements were seen in fitness, physical activity, fatigue and health-related quality of life.

Conclusions

The study findings suggest that high-intensity interval training is acceptable, safe and may offer disease-related benefits for the participants. Participants did experience some symptom exacerbation and further studies are needed to determine the long-term appeal of high-intensity interval training for people with mild multiple sclerosis.

Unhealthy Dieting During the COVID-19 Pandemic: An Opinion Regarding the Harmful Effects on Brain Health

Since 2020, the world has been suffering from a pandemic that has affected thousands of people regardless of socio-economic conditions, forcing the population to adopt different strategies to prevent and control the advance of the disease, one of which is social distancing. Even though social distancing is a safe strategy to reduce the spread of COVID-19, it is also the cause of a rising sedentary behavior. This behavior develops an excess of fat tissue that leads to metabolic and inflammatory disruption related to chronic diseases and mental health disorders, such as anxiety, depression, and sleep issues. Furthermore, the adoption of dietary patterns involving the consumption of ultra-processed foods, higher in fats and sugars, and the reduction of fresh and healthy foods may play a role in the progress of the disease. In this perspective, we will discuss how an unhealthy diet can affect brain function and, consequently, be a risk factor for mental health diseases.

Salutary effects of moderate but not high intensity aerobic exercise training on the frequency of peripheral T-cells associated with immunosenescence in older women at high risk of breast cancer: a randomized controlled trial

Background

Immunosenescence is described as age-associated changes within the immune system that are responsible for decreased immunity and increased cancer risk. Physically active individuals have fewer ‘senescent’ and more naïve T-cells compared to their sedentary counterparts, but it is not known if exercise training can rejuvenate ‘older looking’ T-cell profiles. We determined the effects of 12-weeks supervised exercise training on the frequency of T-cell subtypes in peripheral blood and their relationships with circulating levels of the muscle-derived cytokines (i.e. ‘myokines’) IL-6, IL-7, IL-15 and osteonectin in older women at high risk of breast cancer. The intervention involved 3 sessions/week of either high intensity interval exercise (HIIT) or moderate intensity continuous exercise (MICT) and were compared to an untrained control (UC) group.

Results

HIIT decreased total granulocytes, CD4+ T-cells, CD4+ naïve T-cells, CD4+ recent thymic emigrants (RTE) and the CD4:CD8 ratio after training, whereas MICT increased total lymphocytes and CD8 effector memory (EM) T-cells. The change in total T-cells, CD4+ naïve T-cells, CD4+ central memory (CM) T-cells and CD4+ RTE was elevated after MICT compared to HIIT. Changes in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{\mathrm{V}}{\mathrm{O}}_{2\max } $$\end{document}V˙O2max after training, regardless of exercise prescription, was inversely related to the change in highly differentiated CD8+ EMRA T-cells and positively related to changes in β2-adrenergic receptor (β2-AR) expression on CM CD4+ and CM CD8+ T-cells. Plasma myokine levels did not change significantly among the groups after training, but individual changes in IL-7 were positively related to changes in the number of β2-AR expressing CD4 naïve T cells in both exercise groups but not controls. Further, CD4 T-cells and CD4 naive T-cells were negatively related to changes in IL-6 and osteonectin after HIIT but not MICT, whereas CD8 EMRA T-cells were inversely related to changes in IL-15 after MICT but not HIIT.

Conclusions

Aerobic exercise training alters the frequency of peripheral T-cells associated with immunosenescence in middle aged/older women at high risk of breast cancer, with HIIT (pro-senescent) and MICT (anti-senescent) evoking divergent effects. Identifying the underlying mechanisms and establishing whether exercise-induced changes in peripheral T-cell numbers can alter the risk of developing breast cancer warrants investigation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12979-022-00266-z.

Affective and Enjoyment Responses to Sprint Interval Training in Healthy Individuals: A Systematic Review and Meta-Analysis

Sprint interval training (SIT) is characterized by intensity of "all-out" effort and superior time-efficiency compared to traditional moderate-intensity continuous training (MICT) and has been proposed as one viable solution to address the commonly reported barrier of lack of time for physical activity. While substantial physiological benefits of participation in SIT have been well-documented, the psychological responses to SIT are less clear. No systematic review has been conducted thus far to respond to the assumption that its supramaximal intensity will induce adverse feelings. Therefore, the aim of the present study was to synthesize studies analyzing affective and enjoyment responses to SIT and to compare the responses to SIT with MICT and other high intensity interval training (HIIT) protocols with lower intensities. After searching relevant databases up until 22nd March 2021, twenty-five studies meeting the inclusion criteria were included in the present review. Random effect meta-analysis using the pooled data demonstrated that SIT induced similar post-exercise affective valences during the training compared to MICT and HIIT, but lower affective valences immediately post-exercise compared to MICT. Moreover, affective responses during SIT decreased to negative valences according to the results from most included studies, while low-volume SIT protocols with shorter sprint duration and repetitions induced more positive affective responses. Level of enjoyment after SIT were positive and were comparable to MICT or HIIT. Overall, the results from the existing literature indicate that SIT might cause unpleasant feelings during the training and be perceived less pleasurable than MICT immediately post training but could be a comparably enjoyable modality for healthy individuals in relation to MICT or HIIT, despite its supramaximal intensity. Low-volume SIT may be a realistic option for individuals seeking a time-efficient workout with comparable affective responses to MICT or HIIT.

Systematic Review Registration

[https://www.crd.york.ac.uk/PROSPERO], Identifier [CRD42021284898].

The Immediate and Sustained Effects of Moderate-Intensity Continuous Exercise and High-Intensity Interval Exercise on Working Memory

This study investigated the immediate and delayed effects of moderate-intensity continuous exercise (MICE) and high-intensity interval exercise (HIIE) on working memory. Fifty healthy young adults (mean age = 19.96 ± 1.03 years) engaged in (1) a MICE session, 20 min of continuous running on a treadmill at an intensity of 40–59% of heart rate reserve (HRR); (2) a HIIE session, 10 sets of 1 min running at an intensity of 90% HRR, interspersed by 1 min self-paced walking at 50% HRR; and (3) a control session, resting in a chair and reading books for 24 min. A spatial 2-back task was performed to assess working memory before, immediately after and 30 min after each intervention. Reaction time in the 2-back task was significantly reduced immediately after both MICE and HIIE interventions. The enhanced working memory associated with HIIE sustained for 30 min after the exercise, whereas the beneficial effects associated with MICE returned to the pre-exercise level at 30 min after the exercise. These results suggest that although both MICE and HIIE enhance working memory in young adults, the positive effect sustains longer in HIIE than that in MICE. The current study extends the existing knowledge base by suggesting that improvements in working memory with HIIE last longer than with MICE.

Using Bodyweight as Resistance Can Be a Promising Avenue to Promote Interval Training: Enjoyment Comparisons to Treadmill-Based Protocols

Purpose: Even though multiple training methods appear to be effective to improve cardiorespiratory fitness, they also need to be perceived as tolerable or enjoyable by exercisers to maximize long-term behavioral maintenance. Therefore, the purpose of the current study was to compare perceived enjoyment between whole-body interval training (SIT-WB), treadmill-based interval training (SIT-T) and moderate-intensity continuous training (MICT). Method: Forty-one healthy adult men (age: 23.7 ± 0.7 years, height: 1.79 ± 0.01 m, body mass: 78.5 ± 1.7 kg; VO_2max: 46.7 ± 7.3 ml.kg^-1.min^-1) were randomly assigned to SIT-WB, SIT-T, or MICT and underwent 16 weeks of training (3x/w). SIT-WB and SIT-T completed eight 20 s bouts interspersed by 10 s passive recovery, differing as to the exercise mode performed (i.e., calisthenics exercises and treadmill running, respectively) whereas MICT participants ran for 30 min at an intensity below the second ventilatory threshold. Perceived enjoyment was assessed 10 min post-exercise at weeks 1, 5, 9, 13, and 16, using the Physical Activity Enjoyment Scale. Results: Compliance was high (~90%) across all three training groups (p = .803). All training modes were rated as enjoyable and no significant within- (F_{(4, 152)} = 1.132, p = .344) or between-group (F_{(2, 38)} = 0.662, p = .521) differences were found during the intervention period. Conclusions: These results suggest that SIT-WB can be employed as an enjoyable low-cost alternative to traditional treadmill-based SIT and MICT for up to 16 weeks.

Davies R. The Effect of Exercise Training Intensity on VO2max in Healthy Adults: An Overview of Systematic Reviews and Meta-Analyses

This study aimed to evaluate systematic reviews and meta-analyses that have examined the effect of exercise training on VO2max in healthy individuals at different intensities. Five databases were searched: EBSCOhost, MEDLINE/PubMed, SPORTDiscus, Web of Science, and Google Scholar. Eligibility criteria for selecting reviews included systematic reviews and meta-analyses of healthy adults that examined the effect of lower intensity training (LIT) and/or high intensity training (HIT) on VO2max. Eleven reviews met the eligibility criteria. All reviews were of moderate-to-very strong methodological quality. The included reviews reported data from 179 primary studies with an average of 23 ± 10 studies per review. All reviews included in this overview showed that exercise training robustly increased VO2max at all intensities. Three meta-analyses that compared LIT versus HIT protocols on VO2max reported small/moderate beneficial effects for HIT over LIT; however, the beneficial effects of HIT on VO2max appear to be moderated by training variables other than intensity (e.g., training impulse, interval length, training volume, and duration) and participants' baseline characteristics (e.g., age and fitness levels). Overall, evidence from this overview suggests that the apparent differences between LIT and HIT protocols on VO2max were either small, trivial, or inconclusive, with several methodological considerations required to standardise research designs and draw definitive conclusions.