Effects of High-Intensity Interval Training on People Living with Type 2 Diabetes: A Narrative Review

10-20-30 exercise training improves fitness and health

Intense interval exercise training has been shown to improve performance and health of untrained and trained people. However, due to the exercise intensity causing high-perceived exertion, the participants often do not wish to continue the training. The 10-20-30 training concept consists of low intensity for 30 s, 20 s at a moderate pace, and then 10 s with high intensity either running or cycling. A 10-20-30 training session consist of two to four 5-min blocks. The 10-20-30 training improved fitness and performance as well as lowered blood pressure and body fat of both untrained and trained individuals even with a significant reduction in the training volume. Similarly, hypertensive, diabetic, and asthmatic patients lowered body fat, improved fitness, and performance during a 10-20-30-training intervention period. In addition, hypertensive patients reduced systolic and diastolic blood pressure markedly with the 10-20-30 training twice a week for 8 weeks. Diabetic patients lowered long-term blood sugar (HbA1c), which did not occur with moderate-intensity exercise training. Furthermore, asthmatic patients improved their control of asthma and asthma-related quality of life with the 10-20-30 training. The adherence for the patient groups was high (>80%), and no adverse events were reported. Thus, the 10-20-30 training seems to be time efficient and feasible for untrained and trained individuals as well as patients and may be used in the prevention and treatment of noncommunicable diseases.

Key influences on dysglycemia across Fujian's urban-rural divide

BACKGROUND

Screening and treatment of dysglycemia (prediabetes and diabetes) represent significant challenges in advancing the Healthy China initiative. Identifying the crucial factors contributing to dysglycemia in urban-rural areas is essential for the implementation of targeted, precise interventions.

METHODS

Data for 26,157 adults in Fujian Province, China, were collected using the Social Factors Special Survey Form through a multi-stage random sampling method, wherein 18 variables contributing to dysglycemia were analyzed with logistic regression and the random forest model.

OBJECTIVE

Investigating urban-rural differences and critical factors in dysglycemia prevalence in Fujian, China, with the simultaneous development of separate predictive models for urban and rural areas.

RESULT

The detection rate of dysglycemia among adults was 35.26%, with rates of 34.1% in urban areas and 35.8% in rural areas. Common factors influencing dysglycemia included education, age, BMI, hypertension, and dyslipidemia. For rural residents, higher income (OR = 0.80, 95% CI [0.74, 0.87]), average sleep quality (OR = 0.89, 95% CI [0.80, 0.99]), good sleep quality (OR = 0.89, 95% CI [0.80, 1.00]), and high physical activity (PA) (OR = 0.87, 95% CI [0.79, 0.96]) emerged as protective factors. Conversely, a daily sleep duration over 8 hours (OR = 1.46, 95% CI [1.03, 1.28]) and middle income (OR = 1.12, 95% CI [1.03, 1.22]) were specific risk factors. In urban areas, being male (OR = 1.14, 95% CI [1.02, 1.26]), cohabitation (OR = 1.18, 95% CI [1.02, 1.37]), and central obesity (OR = 1.35, 95% CI [1.19, 1.53]) were identified as unique risk factors. Using logistic regression outcomes, a random forest model was developed to predict dysglycemia, achieving accuracies of 75.35% (rural) and 76.95% (urban) with ROC areas of 0.77 (rural) and 0.75 (urban).

CONCLUSION

This study identifies key factors affecting dysglycemia in urban and rural Fujian residents, including common factors such as education, age, BMI, hypertension, and dyslipidemia. Notably, rural-specific protective factors are higher income and good sleep quality, while urban-specific risk factors include being male and central obesity. These findings support the development of targeted prevention and intervention strategies for dysglycemia, tailored to the unique characteristics of urban and rural populations.

The effect of chronic high-intensity interval training programs on glycaemic control, aerobic resistance, and body composition in type 2 diabetic patients: a meta-analysis

BACKGROUND

Type 2 diabetes is an increasing health problem worldwide. HIIT has been proposed as an exercise alternative to be part of integral type 2 diabetes treatment.

OBJECTIVE

The aim of this meta-analysis was to determine the effect of different types of chronic HIIT on glycaemic control, aerobic resistance, and body composition in individuals above 18 years with T2D.

DESIGN

This meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement and was registered with PROSPERO on November 21st, 2021.

DATA SOURCES

A systematic literature search of the following databases: EbscoHost (Academic Search Ultimate, Fuente Académica Plus, MEDline and SportDiscus), Web of Science, PubMed, and EMBASE between April of 2021 and April of 2023 was conducted.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Eligibility criteria included (1) participants aged ≥ 18 years with a diagnosis of type 2 diabetes, (2) an HIIT protocol with detailed description, (3) control group and/or continuous aerobic training comparison group, (4) report of pre-test and post-test values for at least one of the studied variables (from glycaemic control, aerobic resistance, and/or body composition), and (5) experimental or quasi-experimental intervention design.

ANALYSES

Meta-analysis was made by a pre-post-test between-group analysis following the inverse variance heterogeneity model for each variable, and then, a subgroup analysis by type of HIIT was conducted.

RESULTS

Of the 2817 records obtained, 180 records were included for meta-analysis. Significant improvements were found in the most part of the variables when HIIT was compared to control group, while fat-free mass kept without changes. HIIT vs. continuous aerobic training results showed and advantage in favor of HIIT for fasting blood glycemia. Subgroup analysis refers a possible advantage of SI-HIIT and SIT-HIIT in the improvement of fasting glycemia and SIT-HIIT advantage in HOMA 1-IR decrease.

CONCLUSIONS

HIIT improves glycaemic control, aerobic resistance, and % fat and waist circumference, and kept fat-free mass unchanged in individuals with T2D. SI-HIIT and SIT-HIIT could be better than the other types of HIIT. HIIT benefit is similar to continuous aerobic training except for fasting blood glycemia.

High-Intensity Interval Training Ameliorates High-Fat Diet-Induced Metabolic Disorders via the Cyclic GMP-AMP Synthase-Stimulator of Interferon Gene Signaling Pathway

Metabolic diseases are growing in prevalence worldwide. Although the pathogenesis of metabolic diseases remains ambiguous, the correlation between cyclic GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING) and metabolic diseases has been identified recently. Exercise is an effective intervention protecting against metabolic diseases, however, the role of the cGAS-STING signaling pathway in this process is unclear, and the effect and mechanism of different exercise intensities on metabolic disorders are still unknown. Thus, we explored the association between exercise to ameliorate HFD-induced metabolic disorders and the cGAS-STING signaling pathway and compared the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT). Male C57BL/6 mice (6-8 weeks old) were fed HFD for 8 weeks to establish a metabolic disease model and were subjected to 8-week MICT or HIIT training. Glucose tolerance tests (GTT) and insulin tolerance tests (ITT) were used to assess glucose metabolism. Serum triglyceride (TG) and total cholesterol (TC) were measured to evaluate lipid metabolism. Oil red staining was used to observe the lipid droplets in the gastrocnemius muscle. An enzyme-linked immunosorbent assay was used to detect the serum inflammatory factors IL-6 and IFN-β. The protein expression of the cGAS-STING signaling pathway was detected by the WesTM automatic protein expression analysis system. We reported that HFD induced metabolic disorders with obesity, abnormal glucolipid metabolism, and significant inflammatory responses. Both HIIT and MICT ameliorated the above adverse reactions, but MICT was superior to HIIT in improving glucolipid disorders. Additionally, HIIT significantly increased the expression of STING protein, as well as the phosphorylation of TBKI and the ratio of p-IRF3/IRF3. MICT only increased the expression of STING protein. Our findings suggest that HIIT may alleviate HFD-induced metabolic disorder phenotype through the cGAS-STING signaling pathway. However, the improvement of MICT on metabolic disorder phenotype is less associated with the cGAS-STING pathway, which needs to be further explored.

The effect of high-intensity interval training (HIIT) on protein expression in Flexor Hallucis Longus (FHL) and soleus (SOL) in rats with type 2 diabetes

Purpose

In people with diabetes, one of the problems for patients is muscle wasting and inhibition of the protein synthesis pathway. This study aimed to evaluate the effects of HIIT on protein expression in two skeletal muscles, flexor hallucis longus (FHL) and soleus (SOL) in rats with type 2 diabetes mellitus (T2DM).

Materials and methods

Diabetes initially was induced by streptozotocin (STZ) and nicotinamide. Rats with type 2 diabetes were randomly and equally divided into control (n = 6) and HIIT groups (n = 6). After 8 weeks of training, the content of total and phosphorylated proteins of serine/threonine-protein kinases (AKT1), mammalian target of rapamycin (mTOR), P70 ribosomal protein S6 kinase 1 (P70S6K1), and 4E (eIF4E)-binding protein 1 (4E-BP1) in FHL and SOL muscles were measured by Western blotting. While body weight and blood glucose were also controlled.

Results

In the HIIT training group, compared to the control group, a significant increase in the content of AKT1 (0.003) and mTOR (0.001) proteins was observed in the FHL muscle. Also, after 8 weeks of HIIT training, protein 4E-BP1 (0.001) was increased in SOL muscle. However, there was no significant change in other proteins in FHL and SOL muscle.

Conclusions

In rats with type 2 diabetes appear to HIIT leading to more protein expression of fast-twitch muscles than slow-twitch muscles. thus likely HIIT exercises can be an important approach to increase protein synthesis and prevent muscle atrophy in people with type 2 diabetes.

The effects of aerobic exercise combined with resistance training on inflammatory factors and heart rate variability in middle-aged and elderly women with type 2 diabetes mellitus

OBJECTIVE

This study investigated the effects of aerobic exercise combined with resistance training on serum inflammatory factors and heart rate variability (HRV) in women with type 2 diabetes mellitus (T2DM).

METHODS

A total of 30 patients with diabetic cardiovascular autonomic neuropathy (DCAN) were randomly divided into a control group (n = 15) and an exercise group (n = 15). The control group was treated with routine hypoglycemic drugs, while the exercise group was treated with routine hypoglycemic drugs + resistance training (AE + RT). The levels of fasting plasma glucose (FBG), two-hour plasma glucose (2hPG), serum inflammatory factors C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were measured before and after the intervention. The HRV was evaluated by 24-h ambulatory electrocardiogram.

RESULTS

After the intervention, the levels of FBG, 2hPG, serum inflammatory factors, IL-6 and TNF-α in the exercise group were significantly lower than those in the control group (p < .05) with no significant differences in serum CRP (p > .05). After the intervention, the HRV time domain and frequency domain indexes in the two groups were significantly improved compared with those before the exercise experiment (p < .01) and with no significant difference in (lnlf) (p > .05). The time-domain indexes, i.e., SDNN and RMSSD, as well as the frequency domain index, i.e., (lnhf), were significantly higher in the exercise group than in the control group, whereas lnlf/lnhf were significantly lower than those in the control group (p < .05).

CONCLUSIONS

Compared with routine hypoglycemic drug therapy, combining aerobic exercise and resistance training helped to reduce the level of blood glucose and serum inflammatory factors in T2DM patients with DCAN, and improved autonomic nerve function.

Safety of High-Intensity, Low-Volume Interval Training or Continuous Aerobic Training in Adults With Metabolic Syndrome

OBJECTIVE

The aim of the study was to evaluate the safety of high-intensity, low-volume interval training (HIIT-low volume) compared with moderate-intensity continuous aerobic training (MICT) in adults with metabolic syndrome.

METHODS

This is a controlled, randomized, clinical trial in patients without history of ischemic heart disease or diabetes, who underwent a supervised, 3 sessions/week, 12-week treadmill exercise program. The HIIT-low volume (n = 29) sessions consisted of 6 intervals with 1-minute, high-intensity phases at 90% of peak oxygen consumption (VO2peak). The MICT (n = 31) trained at 60% of VO2peak for 30 minutes. A new approach to record and classify all clinical events according to possible causality based on Naranjo's algorithm was developed.

RESULTS

Patients were 50.8 ± 6.0 years old, 70% women, with body mass index of 30.6 ± 4.0 kg/m2 and VO2peak of 29.0 ± 6.3 mL·kg-1·min-1. In total, 60 clinical events were recorded in the HIIT-low volume group and 48 in the MICT group, with 59.3% classified as general disease. Only 21 events were classified as adverse reactions possibly related to exercise, without any serious adverse reactions. Both interventions had a similar incidence of musculoskeletal events (incidence rate ratio, 1.1; 95% confidence interval, 0.6-1.8), but HIIT-low volume had a higher incidence of cardiovascular events (incidence rate ratio, 2.9; 95% CI, 0.4-22.8) after adjusting for age, sex, and body mass index (HIIT-low volume: chest pain [n = 1] and symptoms of venous insufficiency of lower limbs [n = 2]; MICT: chest pain [n = 1]).

CONCLUSIONS

The HIIT-low volume and MICT are safe in patients with metabolic syndrome. We recommend a muscle-conditioning program prior to both and to avoid HIIT-low volume in treadmill in patients with venous insufficiency of the lower limbs.Trial registration number NCT03087721.

American Medical Society for Sports Medicine Position Statement on the Care of the Athlete and Athletic Person With Diabetes

ABSTRACT

The American Medical Society for Sports Medicine (AMSSM) developed this position statement to assist physicians and other health professionals in managing athletes and active people with diabetes. The AMSSM selected the author panel through an application process to identify members with clinical and academic expertise in the care of active patients with diabetes. This article reviews the current knowledge and gaps regarding the benefits and risks of various types of exercise and management issues for athletes and physically active people with diabetes, including nutrition and rehabilitation issues. Resistance exercises seem to be beneficial for patients with type 1 diabetes, and the new medications for patients with type 2 diabetes generally do not need adjustment with exercise. In preparing this statement, the authors conducted an evidence review and received open comment from the AMSSM Board of Directors before finalizing the recommendations.

Acute high intensity interval exercise is similarly effective as moderate intensity continuous exercise on plasma glucose control in type 2 diabetic men aged 30 to 50 years: a randomized controlled trial

BACKGROUND

This study aimed to compare the acute effects of high-intensity interval exercise (HIIE) versus moderate-intensity continuous exercise (MICE) on postprandial plasma glucose and insulin concentrations in men aged 30-50 years with type 2 diabetes (T2D), hoping to provide empirical evidence for the effects of different exercise types on glucose management in T2D patients.

METHODS

14 men with type 2 diabetes (T2D) underwent a randomized three crossover intervention: HIIE with cycling; energy expenditure matched MICE with cycling; and a sedentary control (CON)) in postprandial state. Plasma glucose and insulin levels were measured at pre-exercise, post-exercise, 1 h post-exercise, pre-lunch and 1 h post-lunch, respectively. Responses of areas under the curve (AUC) during 4 h from pre-exercise to 1 h post-lunch were also calculated.

RESULTS

Both HIIE and MICE decreased plasma glucose and insulin levels during 4 h experimental period compared to CON, with significant intervention × time interaction effects for glucose (P = 0.001) and insulin (P = 0.006) values evolution. Area under curve (AUCs) for glucose and insulin were reduced in HIIE and MICE compared to CON (P < 0.05), whereas no differences were found between HIIE and MICE.

CONCLUSIONS

Acute HIIE and the matched MICE improve plasma glucose control in the same magnitude in type 2 diabetic men aged 30-50 years.

The effect of eight weeks of moderate and high intensity aerobic training on the gene expression of Mir-145, Wnt3a and Dab2 in the heart tissue of type 2 diabetic rats

Purpose

Pathological hypertrophy of heart tissue has been attributed to changes in some microRNAs and their target genes in heart tissue. This study intended to study the effects of eight weeks of moderate and high intensity aerobic training (MIT&HIT) on the mRNA of Mir-145, Wnt3a, and Dab2 in heart tissue of type 2 diabetic rats.

Methods

To implement this experimental research, 60 male Wistar rats were randomly divided into 6 groups, including Healthy-control (HC), Diabetic-control (DC), Moderate intensity training (MIT), Diabetes-MIT (DMIT), high intensity training (HIT) and Diabetes-HIT (DHIT). The aerobic training was conducted with moderate (50-60% VO2max) and high (85-90% VO2max) intensity, 5 days a week, for 8 weeks. The Mir-145, Wnt3a and Dab2 gene expression in the heart tissue samples was measured by Real Time PCR. Data were analyzed by one-way ANOVA and Tukey post hoc test at the P < 0.05.

Results

Moderate and high intensity aerobic training was associated with non-significant increase in Mir-145 mRNA of Heart tissue in type 2 diabetic rats than the diabetic control group(P < 0.05). Moderate and high intensity aerobic training was associated with significant increase in Wnt3a mRNA (P = 0.001) and significant decrease in Dab-2 mRNA (P = 0.001) of Heart tissue in type 2 diabetic rats than the diabetic control group. The Dab-2 mRNA was significantly lower of heart tissue in the diabetes- high intensity training group than the diabetes- moderate intensity training group (P = 0.001).

Conclusion

It seems that moderate and high intensity aerobic exercise can help regulate the genes of the physiological hypertrophy pathway of the heart tissue in diabetes.

The effect of endurance, resistance training, and supplements on mitochondria and bioenergetics of muscle cells

Bioenergetics is the study of energy flow between biological systems and the surroundings and is measured quantitatively. Energy flow can be affected by many variables, including lifestyle and exercise, where exercise comes in different types; endurance and resistance training play significant roles in enhancing bioenergetics and promoting health. In addition, a supplementary diet supports recovery and energy production. This review aims to study the effect of endurance training, resistance training, and supplement intake on the muscle cell's bioenergetics. As a conclusion of the information presented in this mini-review, it was found that resistance, endurance training, and supplements can increase mitochondrial biogenesis, fat oxidation, myofibril synthesis, and increase VO₂ max.

Inflammatory, antioxidant and glycemic status to different mode of high-intensity training in type 2 diabetes mellitus

BACKGROUND

Exercise has traditionally been used and prescribed as an effective and suitable way to treat type 2 diabetics Mellitus (T2DM). In this regard, we compared inflammatory, antioxidant, and glycemic status to different kinds of high-intensity interval training (strength training, HIIT, and HIIT + ST) in patients with T2DM.

METHODS AND RESULTS

Fifty-nine T2DM patients (age = 45-60 yrs) were randomly divided to strength training (ST) (n = 15), high intensity interval training (HIIT) (n = 16), HIIT + ST (n = 15) or served as control (CON) (n = 13) groups. Experimental groups performed three training sessions/week for 12 weeks. Inflammatory, antioxidant, glycemic factors, and anthropometric parameters were evaluated at baseline and after the 12 weeks of interventions. Training HIIT groups significantly improved antioxidant factors, lipid profile, and glycemic parameters (P ≤ 0.05). Interleukin 6 (IL-6), C-reactive protein (CRP), and tumor necrosis factor-α (TNF-α) significantly decreased in the three training groups. As a result of training, the overall inflammatory and antioxidant status were improved considerably in all three training groups compared to the CON group (P ≤ 0.05). In addition, there were significant differences in CRP at the follow-up values between ST and CON groups (P ≤ 0.05). Exercise time and TC were significantly improved in HIIT than in the CON group (P ≤ 0.05). The results showed a significant difference between the HIIT + ST group and the CON group in VO2_peak (P ≤ 0.05).

CONCLUSIONS

Our results showed improvement in inflammatory factors, antioxidants, and glycemic parameters in all training groups regardless of their type. However, for more benefits in T2DM patients, combination exercises can be suggested.

Effects of different aerobic exercise training on glycemia in patients with type 2 diabetes: A protocol for systematic review and meta analysis

BACKGROUND

Type 2 diabetes is an emergent worldwide health crisis, and rates are growing globally. Aerobic exercise is an essential measure for patients with diabetes, which has the advantages of flexible time and low cost. Aerobic exercise is a popular method to reduce blood glucose. Due to the lack of randomized trials to compare the effects of various aerobic exercises, it is difficult to judge the relative efficacy. Therefore, we intend to conduct a network meta-analysis to evaluate these aerobic exercises.

METHODS

According to the retrieval strategies, randomized controlled trials on different aerobic exercise training will be obtained from China National Knowledge Infrastructure, WanFang, SinoMed, PubMed, Web of Science, EMBASE, and Cochrane Library, regardless of publication date or language. Studies were screened based on inclusion and exclusion criteria, and the Cochrane risk bias assessment tool will be used to evaluate the quality of the literature. The network meta-analysis will be performed in Markov Chain Monte Carlo method and carried out with Stata14 and OpenBUGS software. Ultimately, the evidentiary grade for the results will be evaluated.

RESULTS

Eighteen literatures with a total of 1134 patients were included for the meta-analysis. In glycemia assessment, Tennis (standard mean difference = 3.59, credible interval 1.52, 5.65), had significantly better effects than the named control group. Tennis (standard mean difference = 3.50, credible interval 1.05, 5.59), had significantly better effects than the named Taiji group.

CONCLUSION

All together, these results suggest that tennis may be the best way to improve blood glucose in patients with type 2 diabetes. This study may provide an excellent resource for future control glycemia and may also serve as a springboard for creative undertakings as yet unknown.

The fit-active profile to better reflect the benefits of a lifelong vigorous physical activity participation: mini-review of literature and population data

Physical activity is favourably considered for its effect on metabolic fitness and body composition. This observation is generally supported by observational studies and is concordant with endurance-trained individuals' metabolic and morphological profiles. However, in some contexts, the measurement of physical activity habits may not provide an adequate representation of its benefits. In this paper, we review relevant literature on the respective effects of fitness and physical activity on anthropometric and metabolic variables and the informative potential of a classification based on aerobic fitness and activity indicators. The relevance to defining a profile based on both fitness and activity is reinforced by data from the Quebec Family Study showing that, in both men and women, "fit-active" individuals displayed a much more favourable morphological and metabolic profile than "unfit-inactive" individuals. Moreover, these benefits seemed to be more related to variations in fitness than in physical activity. In summary, evidence suggests that a profile combining information on aerobic fitness and physical activity may better reflect the lifelong impact of physical activity on body composition and health. Novelty: The fit-active profile better reflects the long-term benefits of vigorous physical activity participation on health. The reported benefits seem to be more related to variations in aerobic fitness than to those in physical activity.

A Comparison of the Gluco-Regulatory Responses to High-Intensity Interval Exercise and Resistance Exercise

High-intensity interval exercise and resistance exercise both effectively lower blood glucose; however, it is not clear whether different regulatory mechanisms exist. This randomised cross-over study compared the acute gluco-regulatory and the physiological responses of high-intensity interval exercise and resistance exercise. Sixteen (eight males and eight females) recreationally active individuals, aged (mean ± SD) 22 ± 7 years, participated with a seven-day period between interventions. The high-intensity interval exercise trial consisted of twelve, 30 s cycling intervals at 80% of peak power capacity and 90 s active recovery. The resistance exercise trial consisted of four sets of 10 repetitions for three lower-limb exercises at 80% 1-RM, matched for duration of high-intensity interval exercise. Exercise was performed after an overnight fast, with blood samples collected every 30 min, for two hours after exercise. There was a significant interaction between time and intervention for glucose (p = 0.02), which was, on average (mean ± SD), 0.7 ± 0.7 mmol∙L⁻¹ higher following high-intensity interval exercise, as compared to resistance exercise. Cortisol concentration over time was affected by intervention (p = 0.03), with cortisol 70 ± 103 ng∙mL⁻¹ higher (p = 0.015), on average, following high-intensity interval exercise. Resistance exercise did not induce the acute rise in glucose that was induced by high-intensity interval exercise and appears to be an appropriate alternative to positively regulate blood glucose.

Impact of combined training with different exercise intensities on inflammatory and lipid markers in type 2 diabetes: a secondary analysis from a 1-year randomized controlled trial

Background

Exercise is a well-accepted strategy to improve lipid and inflammatory profile in individuals with type 2 diabetes (T2DM). However, the exercise intensity having the most benefits on lipids and inflammatory markers in patients with T2DM remains unclear. We aimed to analyse the impact of a 1-year combined high-intensity interval training (HIIT) with resistance training (RT), and a moderate continuous training (MCT) with RT on inflammatory and lipid profile in individuals with T2DM.

Methods

Individuals with T2DM (n = 80, aged 59 years) performed a 1-year randomized controlled trial and were randomized into three groups (control, n = 27; HIIT with RT, n = 25; MCT with RT, n = 28). Exercise sessions were supervised with a frequency of 3 days per week. Inflammatory and lipid profiles were measured at baseline and at 1-year follow-up. Changes in inflammatory and lipid markers were assessed using generalized estimating equations.

Results

After adjusting for sex, age and baseline moderate-to-vigorous physical activity (MVPA), we observed a time-by-group interaction for Interleukin-6 (IL-6) in both the MCT with RT (β = − 0.70, p = 0.034) and HIIT with RT (β = − 0.62, p = 0.049) groups, whereas, only the HIIT with RT group improved total cholesterol (β = − 0.03, p = 0.045) and LDL-C (β = − 0.03, p = 0.034), when compared to control. No effect was observed for C-reactive protein (CRP), cortisol, tumour necrosis factor-α (TNF-α), soluble form of the haptoglobin-hemoglobin receptor CD163 (sCD163), triglycerides and HDL-C in both groups (p > 0.05).

Conclusions

Favorable adaptations on IL-6 were observed in both the HIIT and MCT combined with RT groups following a long-term 1-year exercise intervention in individuals with T2DM. However, only the HIIT with RT prevented further derangement of total cholesterol and LDL-C, when compared to the control group. Therefore, in order to encourage exercise participation and improve inflammatory profile, either exercise protocols may be prescribed, however, HIIT with RT may have further benefits on the lipid profile.

Trial registration Clinicaltrials.gov ID: NCT03144505

Chronic aerobic exercise: Autoradiographic assessment of GABA(a) and mu-opioid receptor binding in adult rats

Exercise programs have shown great potential for both the prevention and treatment of substance use disorder (SUD). As exercise has been shown to have potent effects on physical and psychological health, it is reasonable to examine the mechanism of how exercise can be used as an adjunct treatment for addiction. The present study examined the effects of chronic aerobic (treadmill) exercise on both GABA(a) and mu-opioid receptor levels in the brains of male and female rats. GABA(a) receptor binding, measured by [³H] Flunitrazepam, was increased in the cingulate cortex following exercise, but only in females. Mu-opioid receptor expression, measured by [³H] ([D-Ala², N-MePhe⁴, Gly-ol]-enkephalin) (DAMGO), showed no effect of exercise while showing an effect of sex, with increased [³H] DAMGO binding in the brains of sedentary males compared to that of sedentary females. Our findings support the potential role for GABA(a) signaling in the cingulate cortex as part of the mechanism of action of aerobic exercise. These data, along with prior reports, aid our understanding of the neurochemical impact and mechanism of chronic aerobic exercise on neuropsychiatric disease, particularly regarding addiction.

Microvascular Control Mechanism of the Plantar Foot in Response to Different Walking Speeds and Durations: Implication for the Prevention of Foot Ulcers

Physical activity has been recommended by the American Diabetes Association (ADA) as a preventive intervention of diabetes complications. However, there is no study investigating how microvascular control mechanism respond to different walking intensities in people with and without diabetes. The purpose of this study was to assess microvascular control mechanism of the plantar foot in response to various walking speeds and durations in 12 healthy people using spectral analysis of skin blood flow (SBF) oscillations. A 3×2 factorial design, including 3 speeds (3, 6, and 9 km/h) and 2 durations (10 and 20 minutes), was used in this study. Plantar SBF was measured using laser Doppler flowmetry over the first metatarsal head. Borg Rating of Perceived Exertion (RPE) scale and heart rate maximum were used to assess the walking intensity. Wavelet analysis was used to quantify regulations of metabolic (0.0095-0.02 Hz), neurogenic (0.02-0.05 Hz), myogenic (0.05-0.15 Hz), respiratory (0.15-0.4 Hz), and cardiac (0.4-2 Hz) controls. For 10-minute walking, walking at 9 km/h significantly increased the ratio of wavelet amplitudes of metabolic, neurogenic, myogenic, respiratory, and cardiac mechanisms compared with 3 km/h (P < .05). For 20-minute walking, walking at 6 km/h significantly increased the ratio of wavelet amplitudes of metabolic, myogenic, respiratory, and cardiac compared with 3 km/h (P < .05). RPE showed a significant interaction between the speed and duration factors (P < .01). This is the first study demonstrating that different walking speeds and durations caused different plantar microvascular regulations.

High-Intensity Interval Training Versus Moderate-Intensity Continuous Training in Middle-Aged and Older Patients with Type 2 Diabetes: A Randomized Controlled Crossover Trial of the Acute Effects of Treadmill Walking on Glycemic Control

Background: This study aimed to compare the acute effects of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on glycemic control in middle-aged and older patients with type 2 diabetes (T2D), using treadmill walking as aerobic exercise mode. Methods: Fifteen patients with T2D (60.25 ± 3.14 years; glycated hemoglobin 7.03 ± 0.33%; medicated with metformin and/or gliptins), participated in a randomized controlled crossover trial. They underwent three experimental conditions (treadmill walking HIIT session (5 × (3 min at 70% of heart rate reserve (HRR) + 3 min at 30% HRR)); treadmill walking MICT session (30 min at 50% HRR); and a control session of rest (CON)) in random order and in the postprandial state. Measurements of capillary blood glucose (BG) were taken immediately before, during, and until 50 min after the experimental conditions. Results: Both HIIT and MICT treadmill walking sessions reduced BG levels during exercise and laboratory 50 min recovery period compared to CON (time*condition interaction effect; p < 0.001). The effect of HIIT was greater compared with MICT (p = 0.017). Conclusions: Treadmill walking HIIT seems a safe and more effective exercise strategy on immediate acute glycemic control compared with MICT in middle-aged and older patients with T2D under therapy with metformin and/or gliptins. Trial Registration Number: ISRCTN09240628.

A influência do exercício físico na captação de glicose independente de insulina

O diabetes melito é uma desordem metabólica de múltipla etiologia, que se caracteriza por hiperglicemia crônica decorrente de defeitos na secreção e/ou ação da insulina e captação reduzida de glicose nos tecidos periféricos, resultando em resistência à insulina. A partir disso, este artigo aborda aspectos fisiopatológicos do diabetes melito tipo 2 (DM2), tendo como objetivo elucidar as vias de sinalização da insulina no tecido muscular esquelético e como a captação de glicose pode ser prejudicada em um indivíduo resistente à insulina, apontando a prática de exercício físico como recurso não farmacológico e/ou terapia adjacente para a melhora da sensibilidade à insulina e captação de glicose no tecido muscular esquelético. Para tal, foi realizada uma pesquisa de revisão da literatura de materiais já publicados sobre o tema e uma análise qualitativa. A sinalização da proteína quinase ativada por adenosina monofosfato (AMPK), mediada pelo exercício físico pode otimizar a captação de glicose no músculo independente de insulina. Assim, o exercício físico serve como recurso não farmacológico e/ou terapia adjacente para restaurar a sensibilidade da via de sinalização receptor de insulina/substrato do receptor de insulina/fosfatidilinositol-3-quinase/Akt e aumento da atividade da proteína quinase ativada de AMP, para translocação e exocitose de transportadores de glicose tipo 4 (GLUT-4) independente de insulina.

Revisiting the Role of Exercise Countermeasure on the Regulation of Energy Balance During Space Flight

A body mass loss has been consistently observed in astronauts. This loss is of medical concern since energy deficit can exacerbate some of the deleterious physiological changes observed during space flight including cardiovascular deconditioning, bone density, muscle mass and strength losses, impaired exercise capacity, and immune deficiency among others. These may jeopardize crew health and performance, a healthy return to Earth and mission’s overall success. In the context of planning for planetary exploration, achieving energy balance during long-term space flights becomes a research and operational priority. The regulation of energy balance and its components in current longer duration missions in space must be re-examined and fully understood. The purpose of this review is to summarize current understanding of how energy intake, energy expenditure, and hence energy balance are regulated in space compared to Earth. Data obtained in both actual and simulated microgravity thus far suggest that the obligatory exercise countermeasures program, rather than the microgravity per se, may be partly responsible for the chronic weight loss in space. Little is known of the energy intake, expenditure, and balance during the intense extravehicular activities which will become increasingly more frequent and difficult. The study of the impact of exercise on energy balance in space also provides further insights on lifestyle modalities such as intensity and frequency of exercise, metabolism, and the regulation of body weight on Earth, which is currently a topic of animated debate in the field of energy and obesity research. While not dismissing the significance of exercise as a countermeasure during space flight, data now challenge the current exercise countermeasure program promoted and adopted for many years by all the International Space Agencies. An alternative exercise approach that has a minimum impact on total energy expenditure in space, while preventing muscle mass loss and other physiological changes, is needed in order to better understand the in-flight regulation of energy balance and estimate daily energy requirements. A large body of data generated on Earth suggests that alternate approaches, such as high intensity interval training (HIIT), in combination or not with sessions of resistive exercise, might fulfill such needs.

Effects of combined training with different intensities on vascular health in patients with type 2 diabetes: a 1-year randomized controlled trial

Background

Exercise, when performed on a regular basis, is a well-accepted strategy to improve vascular function in patients with type 2 diabetes. However, the exercise intensity that yields maximal adaptations on structural and functional indices in patients with type 2 diabetes remains uncertain. Our objective was to analyze the impact of a 1-year randomized controlled trial of combined high-intensity interval training (HIIT) with resistance training (RT) vs. a combined moderate continuous training (MCT) with RT on structural and functional arterial indices in patients with type 2 diabetes.

Methods

Patients with type 2 diabetes (n = 80) were randomized into an exercise intervention with three groups: control, combined HIIT with RT and combined MCT with RT. The 1-year intervention had 3 weekly exercise sessions. High-resolution ultrasonography of the common carotid artery and central and peripheral applanation tonometry were used to assess the changes in structural and functional arterial indices. Generalized estimating equations were used to model the corresponding outcomes.

Results

After adjusting the models for sex, baseline moderate-to-vigorous physical activity, and mean arterial pressure changes, while using the intention-to-treat analysis, a significant interaction was observed on the carotid intima-media thickness (cIMT) for both the MCT (β = − 4.25, p < 0.01) and HIIT group (β = − 3.61, p < 0.01). However, only the HIIT observed favorable changes from baseline to 1-year on peripheral arterial stiffness indices such as carotid radial arterial pulse wave velocity (β = − 0.10, p = 0.044), carotid to distal posterior tibial artery pulse wave velocity (β = − 0.14, p < 0.01), and on the distensibility coefficient (β = − 0.00, p < 0.01). No effect was found for hemodynamic variables after the intervention.

Conclusions

Following a 1-year intervention in patients with type 2 diabetes, both the MCT and HIIT group reduced their cIMT, whereas only the HIIT group improved their peripheral arterial stiffness indices and distensibility coefficient. Taken together, HIIT may be a meaningful tool to improve long-term vascular complications in type 2 diabetes.

Trial registration clinicaltrials.gov ID: NCT03144505

Effectiveness of high-intensity interval training combined with resistance training versus continuous moderate-intensity training combined with resistance training in patients with type 2 diabetes: A one-year randomized controlled trial

AIMS

To evaluate the impact of one-year high intensity interval training (HIIT) combined with resistance training (RT) vs continuous moderate intensity training (MCT) combined with RT on glycaemic control, body composition and cardiorespiratory fitness (CRF) in patients with type 2 diabetes.

MATERIALS AND METHODS

A randomized controlled trial included 96 participants with type 2 diabetes for a one-year supervised exercise intervention with three groups: Control, HIIT with RT and MCT with RT). The control group received standard counseling regarding general PA guidelines, with no structured exercise sessions. The main outcome variable was HbA1c (%). Secondary outcomes were other glycaemic variables, body composition, anthropometry measurements, CRF and enjoyment of exercise. Generalized estimating equations (GEE) were used to model outcomes.

RESULTS

Among the 96 participants enrolled in the intervention, 80 were randomized, with a mean (SD) age of 58.5 years (7.7) and a mean HbA1c of 7.2% (1.6). After adjusting the model for sex and total moderate-to-vigorous physical activity (MVPA), we found that both the MCT with RT (β, 0.003; P, 0.921) and the HIIT with RT (β, 0.025; P, 0.385) groups had no effect on HbA1c. A favourable effect was observed in the MCT with RT group, with a reduction in whole body fat index (β, -0.062; P, 0.022), android fat index (β, -0.010; P, 0.010) and gynoid fat index (β, -0.013; P, 0.014). Additionally, CRF increased during the intervention, but only in the MCT with RT group (β, 0.185; P, 0.019).

CONCLUSIONS

The results from this study suggest that there was no effect of either MCT with RT or HIIT with RT on glycaemic control in individuals with type 2 diabetes. However, the combination of MCT and RT improved body composition and CRF following a one-year intervention.

Accuracy of Wrist-Worn Activity Monitors During Common Daily Physical Activities and Types of Structured Exercise: Evaluation Study

BACKGROUND

Wrist-worn activity monitors are often used to monitor heart rate (HR) and energy expenditure (EE) in a variety of settings including more recently in medical applications. The use of real-time physiological signals to inform medical systems including drug delivery systems and decision support systems will depend on the accuracy of the signals being measured, including accuracy of HR and EE. Prior studies assessed accuracy of wearables only during steady-state aerobic exercise.

OBJECTIVE

The objective of this study was to validate the accuracy of both HR and EE for 2 common wrist-worn devices during a variety of dynamic activities that represent various physical activities associated with daily living including structured exercise.

METHODS

We assessed the accuracy of both HR and EE for two common wrist-worn devices (Fitbit Charge 2 and Garmin vívosmart HR+) during dynamic activities. Over a 2-day period, 20 healthy adults (age: mean 27.5 [SD 6.0] years; body mass index: mean 22.5 [SD 2.3] kg/m²; 11 females) performed a maximal oxygen uptake test, free-weight resistance circuit, interval training session, and activities of daily living. Validity was assessed using an HR chest strap (Polar) and portable indirect calorimetry (Cosmed). Accuracy of the commercial wearables versus research-grade standards was determined using Bland-Altman analysis, correlational analysis, and error bias.

RESULTS

Fitbit and Garmin were reasonably accurate at measuring HR but with an overall negative bias. There was more error observed during high-intensity activities when there was a lack of repetitive wrist motion and when the exercise mode indicator was not used. The Garmin estimated HR with a mean relative error (RE, %) of -3.3% (SD 16.7), whereas Fitbit estimated HR with an RE of -4.7% (SD 19.6) across all activities. The highest error was observed during high-intensity intervals on bike (Fitbit: -11.4% [SD 35.7]; Garmin: -14.3% [SD 20.5]) and lowest error during high-intensity intervals on treadmill (Fitbit: -1.7% [SD 11.5]; Garmin: -0.5% [SD 9.4]). Fitbit and Garmin EE estimates differed significantly, with Garmin having less negative bias (Fitbit: -19.3% [SD 28.9], Garmin: -1.6% [SD 30.6], P<.001) across all activities, and with both correlating poorly with indirect calorimetry measures.

CONCLUSIONS

Two common wrist-worn devices (Fitbit Charge 2 and Garmin vívosmart HR+) show good HR accuracy, with a small negative bias, and reasonable EE estimates during low to moderate-intensity exercise and during a variety of common daily activities and exercise. Accuracy was compromised markedly when the activity indicator was not used on the watch or when activities involving less wrist motion such as cycle ergometry were done.

Is Oxygen Uptake Measurement Enough to Estimate Energy Expenditure During High-Intensity Intermittent Exercise? Quantification of Anaerobic Contribution by Different Methods

Purpose: The aim of the present study was to compare the contributions of the anaerobic pathway as determined by two different methods and energy expenditure during a typical high-intensity intermittent exercise (HIIE) protocol.

Methods: A descriptive research design was utilized in which thirteen physically active men performed six experimental sessions consisting of an incremental test (session 1), submaximal tests at 40, 50, 60, 70, 75, 80, 85, 90% of velocity associated with maximum oxygen uptake (vV˙O_2max) with two intensities per session (sessions 2–5), and the HIIE protocol (session 6; 10 efforts of 1 min at vV˙O_2max interspersed by 1 min of passive recovery). The estimation of anaerobic energy system contribution was calculated by: (a) the excess post-exercise oxygen consumption plus delta lactate method and (b) the accumulated oxygen deficit method using the difference between predicted oxygen demand from the submaximal tests of varying intensities and accumulated oxygen uptake during HIIE. Estimation of aerobic energy system contribution was calculated through the measurement of oxygen consumption during activity. Total EE during the entire HIIE protocol (efforts + recovery) and for the efforts only were calculated from each method.

Results: For efforts + recovery and efforts only, anaerobic contribution was similar for both methods, and consequently total EE was also equivalent (p = 0.230 for both comparisons). During efforts + recovery, aerobic:anaerobic energy system contribution was (68 ± 4%: 32 ± 4%), while efforts only was (54 ± 5%: 46 ± 5%) with both situations demonstrating greater aerobic than anaerobic contribution (p < 0.001 for both).

Conclusion: Anaerobic contribution seems to be relevant during HIIE and must to be taken into account during total EE estimation; however, the type of method employed did not change the anaerobic contribution or total EE estimates.

Physical Activity Recommendations for Health and Beyond in Currently Inactive Populations

Widespread persistent inactivity makes continued efforts in physical activity promotion a persistent challenge. The precise content of physical activity recommendations is not broadly known, and there are concerns that the general messaging of the guidelines, including the recommendations to perform at least 150 min of at least moderate intensity physical activity per week might seem unattainable for and even actually discourage currently inactive people. Here we show that there are a myriad of ways of being physically active, and provide (in part) out-of-the-box examples of evidence based, pragmatic, easily accessible physical activity regimes below 150 min and/or with lower than moderate intensity that yield meaningful health benefits for currently inactive people.

High-Intensity Interval Training Is Equivalent to Moderate-Intensity Continuous Training for Short- and Medium-Term Outcomes of Glucose Control, Cardiometabolic Risk, and Microvascular Complication Markers in Men With Type 2 Diabetes

We sought to determine the efficacy of 12 weeks high-intensity interval training (HIIT), compared to moderate-intensity continuous training (MICT) on glucose control, cardiometabolic risk and microvascular complication markers in men living with type 2 diabetes (T2D). Both modalities were combined with resistance training (RT). Additionally, the study aimed to determine the medium-term durability of effects. After a 12-week, thrice weekly, training intervention incorporating either MICT+RT (n = 11) or HIIT+RT (n = 12), the study concluded with a 6-month follow-up analysis. The middle-aged study participants were obese, had moderate duration T2D and were taking multiple medications including insulin, statins and beta-blockers. Participants, randomized via the method of minimization, performed MICT (progressing to 26-min at 55% maximum estimated workload [eWLmax]) or HIIT (progressing to two variations in which twelve 1-min bouts at 95% eWLmax interspersed with 1-min recovery bouts, alternated with eight 30-s bouts at 120% eWLmax interspersed with 2:15 min recovery bouts) under supervision at an exercise physiology facility. To account for fixed and random effects within the study sample, mixed-effect models were used to determine the significance of change following the intervention and follow-up phases and to evaluate group^*time interactions. Beyond improvements in aerobic capacity (P < 0.001) for both groups, both training modalities elicited similar group^*time interactions (P > 0.05) while experiencing benefits for glycated hemoglobin (HbA1c; P = 0.01), subcutaneous adiposity (P < 0.001), and heart rate variability (P = 0.02) during the 12-week intervention. Adiposity (P < 0.001) and aerobic capacity (P < 0.001) were significantly maintained in both groups at the 6-month follow-up. In addition, during the intervention, participants in both MICT+RT and HIIT+RT experienced favorable reductions in their medication usage. The study reported the inter-individual variability of change within both groups, the exaggerated acute physiological responses (using exercise termination indicators) that occurred during the interventions as well as the incidence of precautionary respite afforded in such a study sample. To reduce hyperglycaemia, and prevent further deterioration of cardiometabolic risk and microvascular complication markers (in both the short- and medium-term), future strategies that integrate the adoption and maintenance of physical activity as a cornerstone in the treatment of T2M for men should (cognisant of appropriate supervision) include either structured MICT+RT, or HIIT+RT. Clinical Trials Registration Number: ACTRN12617000582358 http://www.anzctr.org.au/default.aspx.