Low intensity endurance exercise targeted for lipid oxidation improves body composition and insulin sensitivity in patients with the metabolic syndrome

Toward Exercise Guidelines for Optimizing Fat Oxidation During Exercise in Obesity: A Systematic Review and Meta-Regression

BACKGROUND

Exercise training performed at maximal fat oxidation (FATmax) is an efficient non-pharmacological approach for the management of obesity and its related cardio-metabolic disorders.

OBJECTIVES

Therefore, this work aimed to provide exercise intensity guidelines and training volume recommendations for maximizing fat oxidation in patients with obesity.

METHODS

A systematic review of original articles published in English, Spanish or French languages was carried out in EBSCOhost, PubMed and Scopus by strictly following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement. Those studies that analyzed maximal fat oxidation (MFO) and FATmax in patients with obesity (body fat > 25% for men; > 35% for women) by calculating substrate oxidation rates through indirect calorimetry during a graded exercise test with short-duration stages (< 10 min) were selected for quantitative analysis. The accuracy of relative oxygen uptake (% peak oxygen uptake [%[Formula: see text]O2peak]) and relative heart rate (% peak heart rate [%HRpeak]) for establishing FATmax reference values was investigated by analyzing their intra-individual and inter-study variation. Moreover, cluster analysis and meta-regression were used for determining the influence of biological factors and methodological procedures on MFO and FATmax.

RESULTS

Sixty-four manuscripts were selected from 146 records; 23 studies only recruited men (n = 465), 14 studies only evaluated women (n = 575), and 27 studies included individuals from both sexes (n = 6434). The majority of the evaluated subjects were middle-aged adults (aged 40-60 y; 84%) with a poor cardiorespiratory fitness (≤ 43 mL·kg-1·min-1; 81%), and the reported MFO ranged from 0.27 to 0.33 g·min-1. The relative heart rate at FATmax (coefficient of variation [CV]: 8.8%) showed a lower intra-individual variation compared with relative oxygen uptake (CV: 17.2%). Furthermore, blood lactate levels at FATmax ranged from 1.3 to 2.7 mmol·L-1 while the speed and power output at FATmax fluctuated from 4 to 5.1 km·h-1 and 42.8-60.2 watts, respectively. Age, body mass index, cardiorespiratory fitness, FATmax, the type of ergometer and the stoichiometric equation used to calculate the MFO independently explained MFO values (R2 = 0.85; p < 0.01). The MFO in adolescents was superior in comparison with MFO observed in young and middle-aged adults. On the other hand, the MFO was higher during treadmill walking in comparison with stationary cycling. Body fat and MFO alone determined 29% of the variation in FATmax (p < 0.01), noting that individuals with body fat > 35% showed a heart rate of 61-66% HRpeak while individuals with < 35% body fat showed a heart rate between 57 and 64% HRpeak. Neither biological sex nor the analytical procedure for computing the fat oxidation kinetics were associated with MFO and FATmax.

CONCLUSION

Relative heart rate rather than relative oxygen uptake should be used for establishing FATmax reference values in patients with obesity. A heart rate of 61-66% HRpeak should be recommended to patients with > 35% body fat while a heart rate of 57-64% HRpeak should be recommended to patients with body fat < 35%. Moreover, training volume must be higher in adults to achieve a similar fat oxidation compared with adolescents whereas exercising on a treadmill requires a lower training volume to achieve significant fat oxidation in comparison with stationary cycling.

A new perspective on special effective interventions for metabolic syndrome risk factors: a systematic review and meta-analysis

Metabolic syndrome (MetS) has the largest global burden of all noncommunicable diseases. Owing to the clinical heterogeneity of MetS, wide variations have been reported in the efficacy of moderate-to-vigorous physical activity (MVPA) and intermittent fasting (IF) for improving MetS. We searched five databases for randomized controlled trials published through December 2021, and 372 participants from 11 studies were included in this meta-analysis. Compared with MVPA alone, IF combined with MVPA had a more significant effect on improving body mass and levels of fasting blood glucose and high-density lipoprotein cholesterol; however, it was ineffective in improving triglycerides level, systolic blood pressure, and diastolic blood pressure. Subgroup analysis showed that, except for blood pressure, time-restricted fasting combined with MVPA had a better effect than alternate-day fasting with MVPA. Meanwhile, when the intervention lasted longer than 8 weeks, the effect of the combined intervention was significantly better than that of MVPA alone. This finding provides a basis for clinicians to manage the health of overweight individuals. This study also showed that Caucasians may be more suitable for the combined intervention than Asians. And the combined intervention may provide a preventive effect for MetS risk factors in healthy populations, although this may be due to the small sample size. In general, this study provides a novel perspective on special interventions for MetS traits.

Long- and Short-Term High-Intensity Interval Training on Lipid Profile and Cardiovascular Disorders in Obese Male Adolescents

This study investigated the effects of short-term and long-term periods (8 and 16 weeks) of high-intensity interval training (HIIT) on cardiovascular components, blood lipids, and 6-min walking test performance in obese young boys (age = 16.2 ± 0.7) with >34% body fat. The participants were split into two groups: severe obesity (SOG; n = 17) and moderate obesity (MOG; n = 16). All participants performed on a cycle ergometer for 16 weeks (3 times per week) of HIIT at 100% peak power output at the ventilatory threshold and recovered at 50% of peak power. Except for BMI, both groups improved all body composition measures after 16 weeks, with a higher percentage of change (Δ) in SOG. The 6-min walking test increased in both groups (p < 0.001). Furthermore, cardiovascular variables, blood lactate concentration at rest and after 5-min post-exercise, blood lipids, and insulin concentrations improved significantly in both groups. After 16 weeks, MOG significantly improved in HR_peak, blood glucose concentration, and rating of perceived exertion (RPE), but the percentage of change (Δ) was higher in SOG for all the other variables. SOG showed a higher (Δ) waist-to-hip ratio, maximum heart rate, resting heart rate, systolic blood pressure, blood lactate at 5-min post-exercise, and triglyceride concentrations after 8 and 16 weeks of training. In conclusion, a long-term HIIT program appears to be an appropriate training approach for obese boys with extra body fat. However, considering the RPE values, short-duration training sessions should be planned.

Exercise training impacts skeletal muscle remodelling induced by metabolic syndrome in ZSF1 rats through metabolism regulation

Metabolic syndrome (MetS), characterized by a set of conditions that include obesity, hypertension, and dyslipidemia, is associated with increased cardiovascular risk. Exercise training (EX) has been reported to improve MetS management, although the underlying metabolic adaptations that drive its benefits remain poorly understood. This work aims to characterize the molecular changes induced by EX in skeletal muscle in MetS, focusing on gastrocnemius metabolic remodelling. ¹H NMR metabolomics and molecular assays were employed to assess the metabolic profile of skeletal muscle tissue from lean male ZSF1 rats (CTL), obese sedentary male ZSF1 rats (MetS-SED), and obese male ZF1 rats submitted to 4 weeks of treadmill EX (5 days/week, 60 min/day, 15 m/min) (MetS-EX). EX did not counteract the significant increase of body weight and circulating lipid profile, but had an anti-inflammatory effect and improved exercise capacity. The decreased gastrocnemius mass observed in MetS was paralleled with glycogen degradation into small glucose oligosaccharides, with the release of glucose-1-phosphate, and an increase in glucose-6-phosphate and glucose levels. Moreover, sedentary MetS animals' muscle exhibited lower AMPK expression levels and higher amino acids' metabolism such as glutamine and glutamate, compared to lean animals. In contrast, the EX group showed changes suggesting an increase in fatty acid oxidation and oxidative phosphorylation. Additionally, EX mitigated MetS-induced fiber atrophy and fibrosis in the gastrocnemius muscle. EX had a positive effect on gastrocnemius metabolism by enhancing oxidative metabolism and, consequently, reducing susceptibility to fatigue. These findings reinforce the importance of prescribing EX programs to patients with MetS.

High Levels of Glycated Hemoglobin (HbA1c) Are Associated with Physical Inactivity, and Part of This Association Is Mediated by Being Overweight

The COVID-19 pandemic has generated substantial changes in the lives of the population, such as increased physical inactivity, which can lead to being overweight and, consequently, repercussions on glucose homeostasis. A cross-sectional study based on the adult population of Brazil was conducted by stratified, multistage probability cluster sampling (October and December 2020). Participants were classified as physically active or inactive during leisure time according to the recommendations of the World Health Organization. HbA1c levels were categorized as normal (≤6.4%) or with glycemic changes (≥6.5%). The mediating variable was being overweight (overweight and obese). Descriptive, univariate, and multivariate logistic regression analyses examined the association between physical inactivity and glycemic changes. Mediation was analyzed using the Karlson-Holm-Breen method to verify the influence of being overweight on the association. We interviewed 1685 individuals, mostly women (52.4%), 35-59 years old (45.8%), race/ethnicity brown (48.1%), and overweight (56.5%). The mean HbA1c was 5.68% (95% CI: 5.58-5.77). Mediation analysis verified that physically inactive participants during leisure time were 2.62 times more likely to have high levels of HbA1c (OR: 2.62, 95% CI: 1.29-5.33), and 26.87% of this effect was mediated by over-weight (OR: 1.30: 95% CI: 1.06-1.57). Physical inactivity at leisure increases the chances of high levels of HbA1c, and part of this association can be explained by being overweight.

A method of determining anaerobic threshold from percutaneous oxygen saturation

The anaerobic threshold (AT) is the point of the aerobic-to-anaerobic metabolic switch. Despite the many clinical applications of AT, this measurement requires sophisticated equipment and skills. Here, we investigated a simple measurement method for AT using percutaneous oxygen saturation (SpO₂) and pulse rate (PR) with a pulse oximeter in a study of exercise stress on healthy volunteers. Twenty individuals (ten men and ten women) were included in the study. Various respiratory parameters, including AT, were measured using conventional analytical methods. The SpO₂ threshold (ST) was calculated using the SpO₂-Slope method. The mean ± standard deviations SpO₂ at ST was 97.8% ± 0.3% in men and 99.0 ± 0.3% in women. The concordance and interchangeability between ST and various five different types of AT, the ventilatory equivalent for oxygen (VE/VO₂_AT), V-Slope (V-Slope_AT), ventilatory equivalent (VE_AT), respiratory exchange ratio (R_AT), and partial pressure of end-tidal oxygen (PETO₂_AT) were generally high, with positive correlation coefficients in the range of [0.68-0.80]. These findings suggest that the SpO₂-Slope method with a pulse oximeter may be a useful and simple method to determine AT compared to conventional methods.

Beyond the Calorie Paradigm: Taking into Account in Practice the Balance of Fat and Carbohydrate Oxidation during Exercise?

Recent literature shows that exercise is not simply a way to generate a calorie deficit as an add-on to restrictive diets but exerts powerful additional biological effects via its impact on mitochondrial function, the release of chemical messengers induced by muscular activity, and its ability to reverse epigenetic alterations. This review aims to summarize the current literature dealing with the hypothesis that some of these effects of exercise unexplained by an energy deficit are related to the balance of substrates used as fuel by the exercising muscle. This balance of substrates can be measured with reliable techniques, which provide information about metabolic disturbances associated with sedentarity and obesity, as well as adaptations of fuel metabolism in trained individuals. The exercise intensity that elicits maximal oxidation of lipids, termed LIPOXmax, FATOXmax, or FATmax, provides a marker of the mitochondrial ability to oxidize fatty acids and predicts how much fat will be oxidized over 45–60 min of low- to moderate-intensity training performed at the corresponding intensity. LIPOXmax is a reproducible parameter that can be modified by many physiological and lifestyle influences (exercise, diet, gender, age, hormones such as catecholamines, and the growth hormone-Insulin-like growth factor I axis). Individuals told to select an exercise intensity to maintain for 45 min or more spontaneously select a level close to this intensity. There is increasing evidence that training targeted at this level is efficient for reducing fat mass, sparing muscle mass, increasing the ability to oxidize lipids during exercise, lowering blood pressure and low-grade inflammation, improving insulin secretion and insulin sensitivity, reducing blood glucose and HbA_1c in type 2 diabetes, and decreasing the circulating cholesterol level. Training protocols based on this concept are easy to implement and accept in very sedentary patients and have shown an unexpected efficacy over the long term. They also represent a useful add-on to bariatric surgery in order to maintain and improve its weight-lowering effect. Additional studies are required to confirm and more precisely analyze the determinants of LIPOXmax and the long-term effects of training at this level on body composition, metabolism, and health.

Effects of high intensity interval training on sustained reduction in cardiometabolic risk associated with overweight/obesity. A randomized trial

Background

Considering the potential greater cardiocirculatory effects of high intensity interval training (HIIT), we hypothesized that a 2-month supervised high volume short interval HIIT would induce greater improvements in CRF and cardiometabolic risk and increase long-term maintenance to physical activity compared to isocaloric moderate intensity continuous training (MICT) in overweight/obesity.

Methods

Sixty (19 females) subjects with overweight/obesity were randomized to three training programs (3 times/week for 2 months): MICT (45 min, 50% peak power output-PPO), HIIT (22 × 1-min cycling at 100% PPO/1-min passive recovery) and HIIT-RM (RM: recovery modulation, i.e. subjects adjusted passive recovery duration between 30s and 2 min). After the intervention, participants no longer benefited from supervised physical activity and were instructed to maintain the same exercise modalities on their own. We assessed anthropometrics, body composition, CRF, fat oxidation, lipid profile, glycemic balance, low-grade inflammation, vascular function, spontaneous physical activity and motivation for eating at three time points: baseline (T0), 4 days after the end of the 2-month supervised training program (T2) and 4 months after the end of the training program (T6).

Results

HIIT/HIIT-RM induced greater improvement in VO_2peak (between +14% and +17%), power output at ventilatory thresholds and at maximal fat oxidation rate (+25%) and waist circumference (−1.53 cm) compared to MICT and tended to decrease insulin resistance. During the four-month follow-up period during which exercise in autonomy was prescribed, HIIT induced a greater preservation of CRF, decreases in total and abdominal fat masses and total cholesterol/HDL.

Conclusion

We have shown greater short-term benefits induced by a high volume short interval (1 min) HIIT on cardiorespiratory fitness and cardiometabolic risk over an isocaloric moderate intensity continuous exercise in persons with overweight/obesity. We also showed greater long-term effects (i.e. after 4 months) of this exercise modality on the maintenance of CRF, decreases in total and abdominal fat masses and total cholesterol/HDL.

Effects of Long-Term Regular Continuous and Intermittent Walking on Oxidative Stress, Metabolic Profile, Heart Rate Variability, and Blood Pressure in Older Adults with Hypertension

It is documented that regular exercise is beneficial for improving the antioxidant system, metabolic system, cardiac autonomic function, and blood pressure in those with hypertension. In this regard, low-intensity exercise is recommended for older adults, particularly those with chronic diseases. This study aimed to compare the effects of long-term regular continuous walking with intermittent walking on oxidative stress, metabolic profile, heart rate variability, and blood pressure in older adults with hypertension. Forty-three participants with hypertension aged 60–80 years were randomly divided into the continuous or intermittent walking (CON or INT) groups. Participants in the CON group walked for 30 min, 3 days/week for 12 weeks. Participants in the INT group split 30 min walking into 3 identical sessions punctuated by a 1 min rest after each session, 3 days/week for 12 weeks. Antioxidant and oxidative stress markers, metabolic markers, heart rate variability, and blood pressure were evaluated before and after the exercise program. Glutathione (GSH), GSH to GSH disulfide (GSSG) ratio, and total GSH increased significantly, and GSSG and malondialdehyde decreased significantly in both groups ( $p<0.05$ ) without significant differences between groups. Triglycerides, ratio of total cholesterol to high-density lipoprotein cholesterol, and atherosclerogenic index were significantly lower in the CON group than those in the INT group ( $p<0.05$ ). The standard deviation of the NN intervals and root mean square of the successive differences were significantly higher, and low-frequency power was significantly lower in the INT group than that in the CON group ( $p<0.05$ ). No significant changes in blood pressure were noted in both groups, and nor were there any significant differences between groups. Long-term regular continuous and intermittent walking may comparably increase antioxidants, reduce oxidative stress, and be beneficial for improving important blood pressure-related outcomes, including metabolic profile or cardiac autonomic function in older adults with hypertension.

Similar Adaptations to 10 Weeks Concurrent Training on Metabolic Markers and Physical Performance in Young, Adult, and Older Adult Women

It has been proposed that the combination of high-intensity aerobic exercises and resistance training (RT) known as concurrent training (CT) could improve metabolic syndrome (MetS) markers, and that the exercise mixture in CT could dampen muscle anaerobic pathways, a result known as the interference effect. However, there is scarce evidence on its effects in women across different ages. Therefore, we sought to determine the effects of a 10-week CT intervention on MetS markers and endurance performance in adult women and compared age-related differences between young, adult, and older participants. A total of 112 women with >1 MetS risk factors were included in the study. Participants were allocated to different groups according to the following cutoff age ranges: 20-29years (y), n = 25; 30-39y, n = 35; 40-49y, n = 43; and 50-59y, n = 53. Participants performed 10 weeks of CT, including resistance training (RT), involving six major muscle groups, and high-intensity interval training (HIIT) in a cycle ergometer. Anthropometric, cardiovascular, metabolic, and performance outcomes were assessed before and after the intervention. The CT induced significant improvements in waist circumference (WC) (20-29y: -2.5; 30-39y: -4.1; 40-49y: -4.2; 50-59y: -2.8 Δcm) and the distance achieved in the six-minute walking test (6Mwt) (20-29y: +47.6; 30-39y: +66.0; 40-49y: +43.0; 50-59y: +58.6 Δm) across all age groups, without significant differences between groups. In addition, a significant correlation was found between 6Mwt and WC, independent of age. In conclusion, our results showed that a 10-week CT intervention improved MetS risk factors in women, suggesting that the beneficial effects promoted by CT are independent of age and confirming CT as an effective, age-independent training regimen to improve metabolic health in women.

Nordic Walking at Maximal Fat Oxidation Intensity Decreases Circulating Asprosin and Visceral Obesity in Women With Metabolic Disorders

Objective

Excess visceral adipose tissue is associated with insulin resistance and other metabolic disorders, including deregulation of adipokine secretion, which may be corrected by aerobic exercise training. Asprosin is a novel adipokine responsible for the regulation of appetite and the release of glucose from the liver, and its levels are pathologically elevated in obesity. The aim of the study was to evaluate the effects of 8-week Nordic walking (NW) training at maximal fat oxidation intensity (FAT_max) on changes in body mass, as well as those in insulin resistance and asprosin levels among young women with visceral obesity and metabolic disorders.

Materials and Methods

The study was completed by 14 women (30.14 ± 3.63 years) representing low levels of physical activity, visceral obesity (waist circumference 105.50 ± 14.87 cm, BMI 33.85 ± 5.48 kg/m²) and with metabolic disorders, who for 8 weeks (three times a week, 60 min), participated in NW training at the FAT_max intensity (61.92 ± 6.71% HR_max, 42.33 ± 8.69% VO_2max) controlled on the basis of heart rate (114.21 ± 14.10 bpm).

Results

After 4 and 8 weeks of NW training, a significant decrease in the concentration of asprosin, waist and hip circumference (HC), waist-to-height ratio and body adiposity index (BAI) (p < 0.05, large effect size) were found.

Conclusion

The 8-week NW training at an FAT_max intensity decreases the concentration of asprosin in the blood as well as visceral obesity in young women with metabolic disorders.

Effects of sprint interval training on substrate oxidation in adults living with and without obesity: The i-FLEX study

Metabolic flexibility is the ability to adapt substrate oxidation according to metabolic demand. Exercise increases fat oxidation responses in individuals living with obesity; however, limited research exists on the relationship between substrate oxidation and insulin sensitivity after sprint interval training (SIT). The primary objective was to investigate changes in substrate oxidation at rest and during submaximal exercise, and in insulin sensitivity after 4 weeks of SIT in individuals living with or without obesity. The secondary objective was to investigate correlations between changes in substrate oxidation and insulin sensitivity following SIT. Adults living with obesity (n = 16, body mass index (BMI) = 34.1 kg/m2  ± 3.8) and without obesity (n = 18, BMI = 22.9 kg/m2  ± 1.6) took part in a 4-week SIT intervention. Participants completed three sessions of SIT per week, consisting of repeated sets of a 30-s Wingate separated by 4 m of active recovery. Substrate oxidation at rest and during submaximal exercise was measured using VCO2 /VO2 . Insulin sensitivity was calculated using the Matsuda index. No difference in substrate oxidation at rest was observed for either group (p > 0.05), while a significant increase in fat oxidation was observed in individuals living with obesity [F(1,31) = 14.55, p = 0.001] during the submaximal exercise test. A significant decrease in insulin sensitivity was observed among individuals without obesity [F(1,31) = 5.010, p = 0.033]. No correlations were observed between changes in substrate oxidation and insulin sensitivity (p > 0.05). Following SIT, individuals living with obesity increased submaximal fat oxidation compared to individuals without obesity. No correlations were observed between substrate oxidation and insulin sensitivity. Thus, SIT impacts fat oxidation during exercise in individuals living with obesity while having no such influence on insulin sensitivity.

The Effects of Exercise During a 10-Week Basic Military Training Program on the Physical Fitness and the Body Composition of the Greek Naval Cadets

INTRODUCTION

The period of basic military training (BMT) is a sudden change in the individual habits of the trainees and is characterized by significant improvements in body composition such as the percentage of body fat (%BF) and lean body mass (BM). Research has shown that physical activity during the period of BMT lasting 7-10 weeks has positive effects on the physical condition and BM of cadets. The purpose of this study was to examine the effects of training combining cardiovascular conditioning, circuit strength training, swimming, team sports, and obstacle course on physical fitness and body composition during a 10-week BMT period over 4 years in the Hellenic Naval Academy (HNA).

MATERIALS AND METHODS

The sample consisted of 185 Greek cadets of the HNA (age: 18.4 ± 0.7 years, height: 1.77 ± 6.7 m, BM: 72.6 ± 9.1 kg), of which 153 was male (age: 18.3 ± 0.6 years, height: 1.79 ± 5.8 cm, BM: 75.3 ± 7.6 kg) and 32 was female (age: 18.6 ± 0.9 years, height: 1.68 ± 2.8 cm, BM: 59.9 ± 3.1 kg).The cadets participated each year for 4 years in the BMT, performing 94 training sessions, five times a week. The weekly training program included cardiovascular conditioning, circuit strength training, swimming, team sports, and obstacle course. The measurements of the participants before and after BMT were on BM, %BF, and body mass index (BMI); on the number of sit-ups (SU1), push-ups (PU1), and pull-ups (PullU1) in 1 minute; and on the 12-minute aerobic Cooper test (12-min run).

RESULTS

The results of the study showed that the BM of the cadets decreased significantly by 2.5%, (t184 = 17.591, P < .01), in men by 2.7% (t152 = 16.243, P < .01) and in women by 2.2% (t31 = 9.280, P < .01). Body mass index (BMI) decreased significantly by 2.6% (t184 = 17.681, P < .01), in men by 3.0% (t152 = 16.046, P < .01) and in women by 2.3% (t31 = 9.224, P < 0.01). Reduction in %BF in all cadets reached 11.3% (t184 = 8.134, P < .01), for men -14.8% (t152 = 8.918, P < .01) and women -2.1% (t31 = 0.860, P > .05) without significant differences between the measurements.The number of push-ups in 1 minute (PU1) significantly increased by 27.6% (t184 = -27.813, P < .01), in women by +35.6% (t31 = 13,864, P < .01). The number of sit-ups in 1 minute (SU1) significantly increased by 27.3% (t184 = -30.501, P < .01), for men +28.8% (t152 = -29.862, P < .01). The number of pull-ups in 1 minute (PullU1) reached 20.8% (t184 = -13.426, P < .01) in total, at similar levels in men (t152 = -13.918, p < .01) and women (t31 = -2.820, P < .01).On the 12-min run, the significant improvement exceeded 10.8% (t184 = -45.289, P < .01), in men by 11.1% (t152 = -45.222, P < .01) while in women by 9.0% (t31 = 15.709, P < .01).

CONCLUSIONS

The results of this study showed that 10 weeks of BMT, which combined cardiovascular conditioning, circuit strength training, swimming, team sports, and obstacle course improved the body composition, cardiorespiratory endurance, and the strength of the Greek HNA cadets.

Conjoint Associations of Adherence to Physical Activity and Dietary Guidelines With Cardiometabolic Health: The Framingham Heart Study

Background

The conjoint associations of adherence to the recent physical activity and dietary guidelines with the metabolic syndrome (MetS) are incompletely understood.

Methods and Results

We evaluated 2379 FHS (Framingham Heart Study) Third Generation participants (mean age, 47 years; 54.4% women) attending examination cycle 2. We examined the cross‐sectional relations of adherence to the 2018 Physical Activity Guidelines for Americans (binary; moderate‐to‐vigorous physical activity ≥150 versus <150 min/wk) and 2015 Dietary Guidelines for Americans (binary; 2015 Dietary Guidelines for Americans Adherence Index ≥median versus <median [score, 62.1/100]) with prevalence of the MetS using generalized linear models. We also related adherence to guidelines with the incidence of MetS prospectively, using Cox proportional hazards regression with discrete time intervals. Adherence rates to the 2018 Physical Activity Guidelines for Americans (odds ratio [OR], 0.49; 95% CI, 0.40–0.60) and 2015 Dietary Guidelines for Americans (OR, 0.67; 95% CI, 0.51–0.90) were individually associated with lower odds of prevalent MetS, whereas conjoint adherence to both guidelines was associated with the lowest odds of MetS (OR, 0.35; 95% CI, 0.26–0.47) compared with the referent group (nonadherence to both guidelines). Adherence rates to the 2018 Physical Activity Guidelines for Americans (hazard ratio [HR], 0.66; 95% CI, 0.50–0.88) and 2015 Dietary Guidelines for Americans (HR, 0.68; 95% CI, 0.51–0.90) were associated with lower risk of MetS, prospectively. In addition, we observed a 52% lower risk of MetS in individuals who adhered to both guidelines compared with the referent group.

Conclusions

Maintaining both regular physical activity and a healthy diet in midlife may be required for optimal cardiometabolic health in later life.

Is Physical Exercise in Hypoxia an Interesting Strategy to Prevent the Development of Type 2 Diabetes? A Narrative Review

Impaired metabolism is becoming one of the main causes of mortality and the identification of strategies to cure those diseases is a major public health concern. A number of therapies are being developed to treat type 2 diabetes mellitus (T2DM), but few of them focus on situations prior to diabetes. Obesity, aging and insulin resistance are all risk factors, which fortunately can be reversed to some extent. Non-drug interventions, such as exercise, are interesting strategies to prevent the onset of diabetes, but it remains to determine the optimal dose and conditions. In the search of optimizing the effects of physical exercise to prevent T2DM, hypoxic training has emerged as an interesting and original strategy. Several recent studies have chosen to look at the effects of hypoxic training in people at risk of developing T2DM. Therefore, the purpose of this narrative review is to give an overview of all original articles having tested the effects of a single exercise or exercise training in hypoxia on glucose metabolism and other health-related parameters in people at risk of developing T2DM. Taken together, the data on the effects of hypoxic training on glucose metabolism, insulin sensitivity and the health status of people at risk of T2DM are inconclusive. Some studies show that hypoxic training can improve glucose metabolism and the health status to a greater extent than normoxic training, while others do not corroborate the latter. When an additional benefit of hypoxic vs normoxic training is found, it still remains to determine which signaling pathways and molecular mechanisms are involved.

The acute vs. chronic effect of exercise on insulin sensitivity: nothing lasts forever

Supplemental Digital Content is available in the text.

Regular exercise causes chronic adaptations in anatomy/physiology that provide first-line defense for disease prevention/treatment (‘exercise is medicine’). However, transient changes in function that occur following each exercise bout (acute effect) are also important to consider. For example, in contrast to chronic adaptations, the effect of exercise on insulin sensitivity is predominantly rooted in a prolonged acute effect (PAE) that can last up to 72 h. Untrained individuals and individuals with lower insulin sensitivity benefit more from this effect and even trained individuals with high insulin sensitivity restore most of a detraining-induced loss following one session of resumed training. Consequently, exercise to combat insulin resistance that begins the pathological journey to cardiometabolic diseases including type 2 diabetes (T2D) should be prescribed with precision to elicit a PAE on insulin sensitivity to serve as a first-line defense prior to pharmaceutical intervention or, when such intervention is necessary, a potential adjunct to it.

Video Abstract: http://links.lww.com/CAEN/A27

Chronic Effect of Fatmax Training on Body Weight, Fat Mass, and Cardiorespiratory Fitness in Obese Subjects: A Meta-Analysis of Randomized Clinical Trials

Exercise training performed at the maximal fat oxidation intensity (FMT) stands out as a potential treatment of overweight and obesity. This work is a meta-analysis of randomized clinical trials of studies about the effect of FMT on fat mass and maximal oxygen consumption using PubMed, SCOPUS, EBSCOhost, and ScienceDirect as databases. Two independent reviewers selected 11 trials from 356 publications identified by the following keywords: fatmax, lipoxmax, maximal fat oxidation, peak of fat oxidation, physical training, physical exercise, body fat (BF), fat mass, overweight, and obesity. The risk of bias was assessed following the Cochrane Guidelines. The pooled mean difference was computed for each outcome with the random-effects model and the inverse-variance method. The meta-analysis was performed with the RevMan software v 5.3, and the heterogeneity across studies by the I². The statistical significance was accepted at p < 0.05. Results showed that the FMT reduced body weight (MD = -4.30 kg, p < 0.01, I² = 0%), fat mass (MD = -4.03 kg, p < 0.01, I² = 0%), and waist circumference (MD = -3.34 cm, p < 0.01). Fat-free mass remains unchanged (MD = 0.08 kg, p = 0.85), but maximal oxygen consumption increased (MD = 2.96 mL∙kg^-1∙min^-1, p < 0.01, I² = 0%). We conclude that FMT at short and medium-term (eight to twenty weeks) reduces body weight and BF, increasing cardiovascular fitness in low physical fitness people with obesity.

Physiological response and cardiorespiratory adaptation after a 6-week Nordic Walking training targeted at lipid oxidation in a group of post-menopausal women

This study examined the effects of a 6-week Nordic Walking (NW) training, at the intensity corresponding to the dominance of lipid metabolism, on the levels of selected physiological indices, the haemodynamic indices of the cardiovascular system and physical fitness in sedentary women older than 55 years of age. In addition, the physiological response of the female body to the walking effort on treadmill with poles (NW) and without poles (W) was compared and the influence of training on this response was determined. A single group study with a pre-test/post-test study design was conducted. Eighteen women performed NW controlled intensity training 3 times a week for 6 weeks. Body composition, resting blood pressure (BP), heart rate (HR), maximum oxygen uptake (VO₂max) as well as circulatory and respiratory indices in two graded walking efforts on mechanical treadmill NW and W were measured before and after training period. The intensity of workouts, which considered the dominance of lipid metabolism, was determined individually, based on the dynamics of changes in the level of physiological indices during the graded intensity NW. After the course of training, body mass, fat mass, resting BP and HR decreased significantly (p < 0.05). HR and respiratory exchange ratio recorded during NW and W at 1.75 m^.s^-1 walking speed decreased, while the oxygen pulse increased (p < 0.05). VO₂max increased significantly (p < 0.05). Before and after the training period HR, oxygen uptake per minute, and energy expenditure during NW were significantly higher than in W (p < 0.05). The study showed that 6-week NW training at the intensity corresponding to the dominance of lipid metabolism can provide improvement in body composition, cardiovascular function and physical performance in previously sedentary women. NW compared to the regular walk with the same speed revealed higher energy expenditure.

Exercise intensity and physical fitness modulate lipoproteins profile during acute aerobic exercise session

Physical inactivity has emerged as an important cardiometabolic risk factor; however, the beneficial impacts of physical exercise according physical fitness status are still unclear. To analyze the lipoproteins and immune-endocrine response to acute aerobic exercise sessions performed at different intensities according physical fitness status and evaluated the gene expression in monocyte cells. Twelve individuals, divided into Low and High VO_2max, performed three randomized acute exercise sessions at low (<60% VO_2max), moderate (60-75% VO_2max), and high (>90% VO_2max) intensities. Blood samples were collected pre, immediately post, and 60 minutes post-exercise to analyze NEFA, triacylglycerol, non-HDL-c, HDL-c, PAI-1, leptin and adiponectin concentrations. Blood samples were collected from another set of twelve individuals for use in monocyte cell cultures to analyze L-CAT, CETP, and AMPK gene expressions. Low VO_2max group pre-exercise exhibited higher postprandial leptin and total cholesterol concentrations than High VO_2max group (p < 0.05). Exercise performed in high-intensity promoted a decreased leptin and NEFA levels (p < 0.05, for both), but for PAI-1 levels was decreased (p < 0.05) only for the Low VO_2max group. Triacylglycerol levels decreased after all exercise sessions (p < 0.05) for both groups, and HDL-c exhibited decrease during moderate-intensity (p < 0.05), but this scenario was attenuated in Low VO_2max group. Low VO_2max individuals exhibit some metabolic-endocrine disruption, and acute aerobic exercise sessions performed at low, moderate, and high intensities are capable of modulating metabolic-endocrine parameters, mainly at high-intensity, in a physical fitness-dependent way, given that Low VO_2max group was more responsive and seem to be able to appropriate more exercise-related benefits.

Alterations of Serum Ser312-Phosphorylated Fetuin-A from Exercise-Induced Moderate Body Weight Loss in Individuals with Obesity

OBJECTIVE

Phosphorylated fetuin-A (pFet-A) inhibits insulin action and has been shown to be associated with obesity and insulin resistance. The objective of this cohort study was to assess the effect of incremental body weight loss on alterations in serum pFet-A and indexes of insulin sensitivity.

METHODS

A total of 16 men with obesity attained a targeted weight loss of 8% to 10% of their initial body weight by achieving an energy expenditure/deficit of 2,000 to 2,500 kcal/wk. Anthropometric assessments and blood samples were obtained every 4 weeks. Weight loss was calculated and partitioned as 2% to 4%, 4% to 6%, 6% to 8%, and 8% to 10% compared with initial body weight.

RESULTS

Targeted body weight loss of 8% to 10% decreased serum pFet-A, pFet-A:Fet-A ratio, fasting insulin, log(homeostasis model assessment of insulin resistance), quantitative insulin sensitivity check index, adipose insulin resistance, and insulin resistance index significantly. Percent changes in serum pFet-A were associated with percent changes in indexes of insulin sensitivity. Unlike insulin sensitivity indexes, which were altered starting with 6% to 8% weight loss, serum pFet-A levels were significantly decreased by 19.6% starting with 2% to 4% weight loss and decreased by 25.6%, 36.8%, and 42.3% with 4% to 6%, 6% to 8%, and 8% to 10% weight loss, respectively.

CONCLUSIONS

This study reports for the first time that the insulin-sensitizing effects of moderate weight loss are associated with a reduction in serum pFet-A levels.

Reinterpreting Cardiorenal Protection of Renal Sodium-Glucose Cotransporter 2 Inhibitors via Cellular Life History Programming

Cardiovascular outcome trials have provided evidence that sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment is associated with remarkably favorable cardiovascular outcomes. Here, we offer a novel hypothesis that may encompass many of these hypothetical mechanisms, i.e., the ability of SGLT2i to modify the trajectory of cell response to a toxic environment through modifications of cellular life history programs, either the defense program or the dormancy program. The choice between these programs is mainly determined by the environment. Hyperglycemia can be considered a toxic determinant able to interfere with the basic programs of cell evolution. While the defense program is characterized by activation of the immune response and anabolic metabolism, the dormancy program is an energy-preserving state with high resistance to environmental stressors, and it has strong analogy with animal hibernation where fuel is stored, metabolic rate is suppressed, and insulin secretion is reduced. The metabolic changes that follow treatment with SGLT2i are reminiscent of the metabolic picture characteristic of the dormancy program. Therefore, we hypothesize that the beneficial cardioprotective effects of SGLT2i may be related to their ability to switch cell life programming from a defense to a dormancy state, thus lending additional benefit.

No Influence of Overweight/Obesity on Exercise Lipid Oxidation: A Systematic Review

Compared to lean counterparts, overweight/obese individuals rely less on lipid during fasting. This deficiency has been implicated in the association between overweight/obesity and blunted insulin signaling via elevated intramuscular triglycerides. However, the capacity for overweight/obese individuals to use lipid during exercise is unclear. This review was conducted to formulate a consensus regarding the influence of overweight/obesity on exercise lipid use. PubMed, ProQuest, ISI Web of Science, and Cochrane Library databases were searched. Articles were included if they presented original research on the influence of overweight/obesity on exercise fuel use in generally healthy sedentary adults. Articles were excluded if they assessed older adults, individuals with chronic disease, and/or exercise limitations or physically-active individuals. The search identified 1205 articles with 729 considered for inclusion after duplicate removal. Once titles, abstracts, and/or manuscripts were assessed, 24 articles were included. The preponderance of evidence from these articles indicates that overweight/obese individuals rely on lipid to a similar extent during exercise. However, conflicting findings were found in eight articles due to the outcome measure cited, participant characteristics other than overweight/obesity and characteristics of the exercise bout(s). We also identified factors other than body fatness which can influence exercise lipid oxidation that should be controlled in future research.

Comparisons of low-intensity versus moderate-intensity combined aerobic and resistance training on body composition, muscle strength, and functional performance in older women

OBJECTIVE

This study aimed to examine the effects of exercise order of combined aerobic and low- or moderate-intensity resistance training into the same session on body composition, functional performance, and muscle strength in healthy older women. Furthermore, this study compared the effects of different (low- vs moderate-) intensity combined training.

METHODS

A total of 60 healthy older women (age 61-81 y) were randomly assigned to five groups that performed aerobic exercise before low-intensity resistance training (AR-L, n = 12) or after resistance training (RA-L, n = 12), performed aerobic exercise before moderate-intensity resistance training (AR-M, n = 12) or after resistance training (RA-M, n = 12), or nonintervention control conditions (CON, n = 12). Body composition, functional performance, and muscle strength were evaluated before and after the 10-week training.

RESULTS

No effects of exercise order of combined aerobic and low- or moderate-intensity resistance training (AR-L vs RA-L, AR-M vs RA-M) were observed in body composition, functional performance, or muscle strength, whereas the effects of training intensity of combined training (AR-L vs AR-M, RA-L vs RA-M) were observed on functional performance. All combined trainings significantly increased muscle strength and gait ability (P < 0.01, respectively). Functional reach test significantly increased in the AR-M and RA-M groups (P < 0.01, respectively), and there were significant group differences between AR-L and AR-M (P = 0.002), RA-L and RA-M (P = 0.014).

CONCLUSIONS

Preliminary findings suggest that combined aerobic and low- or moderate-intensity resistance training increases muscle strength and improves gait ability, regardless of the exercise order. Also, greater improvement in dynamic balance capacity, a risk factor associated with falling, is observed in moderate-intensity combined training.

Domain and intensity of physical activity are associated with metabolic syndrome: A population-based study

Introduction

Little is known on how the domain and intensity of physical activity (PA) associates with metabolic syndrome (MetS). The aim of this study was to examine associations between PA domains (leisure-time, domestic, active transport, total walking and total PA), PA intensities (light, moderate and vigorous) and PA levels with MetS in the general adult population.

Methods

Cross-sectional study. Anthropometry, blood biochemistry, 79-item PA-questionnaire, lifestyle and medical history were evaluated in a representative sample of Canary Island adults (n = 6,729). MetS was diagnosed using the harmonized IDF-NHLBI-AHA criteria. T-test and multivariable logistic regression was used to analyse associations between PA domains and intensities with MetS vs. no MetS, controlling for socio-demographic, lifestyle, family antecedents and body mass index (BMI).

Results

For each MET-h/day spent in moderate-vigorous PA intensities, as well as in recreational domain, active transport, total walking and total PA, the odds of MetS decreased between 3–10%. Energy expenditure exclusively in light and domestic PAs was not associated with MetS, however it was important to achieve a total PA level of 3 MET-h/day, which reduced the odds of MetS by 23%. This reduction was blunted in those with more than 2 h/d of TV watching time. A PA level of 3 MET-h/d also nullified the risk of MetS in those with low PA and high TV consumption.

Conclusions

Some types of leisure time PAs may contribute more than others to reducing MetS. Light and domestic PA play a complementary role in enhancing energy expenditure in the general population. TV watching time above 2 h/d counteracted the MetS risk reduction associated with PA level, but PA level also reduced the risk of METs presented by those with a low level of PA and an excess TV watching time. Physical activity explains a greater amount of the variance of MetS than any other factors of lifestyle, education, sex and family history, and substantially mitigates the strong association of age and BMI with MetS.

A new in vitro muscle contraction model and its application for analysis of mTORC1 signaling in combination with contraction and beta-hydroxy-beta-methylbutyrate administration

Several food constituents augment exercise-induced muscle strength improvement; however, the detailed mechanism underlying these combined effects is unknown because of the lack of a cultured cell model for evaluating the contraction-induced muscle protein synthesis level. Here, we aimed to establish a new in vitro muscle contraction model for analyzing the activation of mammalian target of rapamycin complex 1 (mTORC1) signaling. We adopted the tetanic electric stimulation of 50 V at 100 Hz for 10 min in L6.C11 myotubes. Akt, ERK1/2, and p70S6K phosphorylation increased significantly after electrical pulse stimulation (EPS), compared to untreated cells. Next, we used this model to analyze mTORC1 signaling in combination with exercise and beta-hydroxy-beta-methylbutyrate (HMB), an l-leucine metabolite. p70S6K phosphorylation increased significantly in the EPS+HMB group compared to that in the EPS-alone group. These findings show that our model could be used to analyze mTORC1 signaling and that HMB enhances muscle contraction-activated mTORC1 signaling.

Exercise as 'precision medicine' for insulin resistance and its progression to type 2 diabetes: a research review

Type 2 diabetes and obesity epidemics are in effect in the United States and the two pathologies are linked. In accordance with the growing appreciation that ‘exercise is medicine,’ it is intuitive to suggest that exercise can play an important role in the prevention and/or treatment of these conditions. However, if exercise is to truly be considered as a viable alternative to conventional healthcare prevention/treatment strategies involving pharmaceuticals, it must be prescribed with similar scrutiny. Indeed, it seems reasonable to posit that the recent initiative calling for ‘precision medicine’ in the US standard healthcare system should also be applied in the exercise setting. In this narrative review, we consider a number of explanations that have been forwarded regarding the pathological progression to type 2 diabetes both with and without the concurrent influence of overweight/obesity. Our goal is to provide insight regarding exercise strategies that might be useful as ‘precision medicine’ to prevent/treat this disease. Although the etiology of type 2 diabetes is complex and cause/consequence characteristics of associated dysfunctions have been debated, it is well established that impaired insulin action plays a critical early role. Consequently, an exercise strategy to prevent/treat this disease should be geared toward improving insulin sensitivity both from an acute and chronic standpoint. However, research suggests that a chronic improvement in insulin sensitivity only manifests when weight loss accompanies an exercise intervention. This has resonance because ectopic fat accumulation appears to represent a central component of disease progression regardless of whether obesity is also part of the equation. The cause/consequence characteristics of the relationship between insulin resistance, pathological fat deposition and/or mobilsation, elevated and/or poorly-distributed lipid within myocytes and an impaired capacity to use lipid as fuel remains to be clarified as does the role of muscle mitochondria in the metabolic decline. Until these issues are resolved, a multidimensional exercise strategy (e.g., aerobic exercise at a range of intensities and resistance training for muscular hypertrophy) could provide the best alternative for prevention/treatment.

Hypoxic Training Improves Normoxic Glucose Tolerance in Adolescents with Obesity

PURPOSE

This study aimed to test whether environmental hypoxia could potentiate the effects of exercise training on glucose metabolism and insulin sensitivity.

METHODS

Fourteen adolescents with obesity were assigned to 6 wk of exercise training either in normoxic or in hypoxic conditions (FiO2 15%). Adolescents trained three times per week for 50-60 min, including endurance and resistance exercises. Oral glucose tolerance test, blood and morphological analyses, and physical performance tests were performed before and after the training period.

RESULTS

After training, hypoxia, but not normoxia, decreased the area under the curve of plasma insulin (-49%; P = 0.001) and glucose levels (-14%; P = 0.005) during oral glucose tolerance test. Decreased plasma triglycerides levels (P = 0.03) and increased maximal aerobic power (P = 0.002), work capacity at 160 bpm (P = 0.002), and carbohydrate consumption during exercise (P = 0.03) were measured only in the hypoxic group.

CONCLUSIONS

Hypoxic exercise training was particularly efficient at improving glucose tolerance and insulin response to a glucose challenge in adolescents with obesity. These results suggest that exercise training in hypoxia could be an interesting strategy against insulin resistance and type 2 diabetes development in adolescents with obesity.

Effect of 24-week repeated short-time walking based training program on physical fitness of black Cameroonian obese women

This study aimed to examine the effects of a training program based on repetition of short-time walk sequences on cardiorespiratory response, physical performance and metabolic parameters in black Cameroonian obese women. One hundred thirty-nine obese women (body mass in-dex [BMI]>30 kg/m2) were divided into three groups: premenopausal (Pre-M; 39.7±7.9 yr; n=48), postmenopausal (Post-M; 55.0±2.5 yr; n=61) and control group (CONT; 48.7±9.4 yr; n=30). Only Pre-M and Post-M completed 24-week repeated short-time walking program. An-thropometric, cardiorespiratory, metabolic parameters, and the 6-min walk distance (6MWD) were measured at baseline (S1), 12 weeks follow-up (S2), and 2 days after the last session (S3). Significant changes were observed in weight, BMI, fatty mass and 6MWD in Pre-M and Post-M after 24 weeks. The waist and hip circumferences, percentages of water, muscle mass and bone mass changed in Post-M. Total cholesterol, triglycerides, low density lipoprotein and forced expiratory volumes in 1 and 6 sec showed significant improvements in Pre-M and Post-M. High density lipoprotein increased only in Post-M (0.5±0.2 g/L vs 0.7±0.1 g/L, P=0.041). In conclusion, this training modality could constitute an option for obese women rehabilitation.

Exercise training at the intensity of maximal fat oxidation in obese boys

The objectives of this study were to explore the effects of 10 weeks of exercise training at the intensity of maximal fat oxidation rate (FATmax) on body composition, cardiovascular fitness, and functional capacity in 8- to 10-year-old obese boys. This is a school-based interventional study. Twenty-six obese boys and 20 lean boys were randomly allocated into the exercise and control groups. Measurements of body composition, FATmax through gas analyses, predicted maximal oxygen uptake, and functional capacity (run, jump, abdominal muscle function, and body flexibility) were conducted at baseline and at the end of experiments. Two exercise groups participated in 10 weeks of supervised exercise training at individualized FATmax intensities, for 1 h per day and 5 days per week. FATmax training decreased body mass (-1.0 kg, p < 0.05), body mass index (-1.2 kg/m(2), p < 0.01), fat mass (-1.2 kg, p < 0.01), and abdominal fat (-0.13 kg, p < 0.01) of the trained obese boys. Their cardiovascular fitness (p < 0.05) and body flexibility (p < 0.05) were also improved after training. The lean boys showed improvements in cardiovascular fitness after training (p < 0.05). FATmax training increased the FATmax in obese boys from 0.35 ± 0.12 g/min to 0.38 ± 0.13 g/min, but this change was not statistically significant. In addition, there was no change in daily energy intake for all participants before and after the experimental period. Results of this study suggest that FATmax is an effective exercise training intensity for the treatment of childhood obesity.

Effects of Qigong Exercise on Biomarkers and Mental and Physical Health in Adults With at Least One Risk Factor for Coronary Artery Disease

Current medical technology permits the early detection of risk factors for coronary artery disease (CAD) in adults, and interventions are available to prevent CAD-related morbidity and mortality. The goal of this study was to determine the effectiveness of a Qigong exercise intervention in improving biomarker levels and mental and physical health outcomes in community-dwelling adults diagnosed with CAD risk factors, in a southern Taiwanese city. Participants were randomly assigned to an experimental ( n = 84) group that participated in a 60-min Qigong group session 3 times per week for 3 months or a control ( n = 61) group that did not receive the intervention. Self-perceived mental and physical health assessed with the Chinese Health Questionnaire-12, and body fat percentage were measured at baseline and 6, 12, and 16 weeks. Blood samples were collected at baseline and 12 weeks for analysis of lipid profiles, high-sensitivity C-reactive protein (hs-CRP), glycated hemoglobin (HbA1c), and fasting plasma sugar. Linear mixed model analyses revealed that experimental participants had significantly improved perceived mental and physical health and body fat percentage compared to the control group at 6 and 12 weeks but not 16 weeks. The lipid profiles were significantly more improved in the Qigong group than in the control group at 12 weeks. Qigong exercise, however, had no significant effects on hs-CRP, HbA1c, or fasting plasma sugar. Findings suggest that Qigong exercise improves a limited number of CAD risk factors in community-dwelling adults aged 40 years and over.

Individualized Exercise Training at Maximal Fat Oxidation Combined with Fruit and Vegetable-Rich Diet in Overweight or Obese Women: The LIPOXmax-Réunion Randomized Controlled Trial

OBJECTIVES

Lifestyle combined interventions are a key strategy for preventing type-2 diabetes (T2DM) in overweight or obese subjects. In this framework, LIPOXmax individualized training, based on maximal fat oxidation [MFO], may be a promising intervention to promote fat mass (FM) reduction and prevent T2DM. Our primary objective was to compare three training programs of physical activity combined with a fruit- and vegetable-rich diet in reducing FM in overweight or obese women.

DESIGN AND SETTING

A five months non-blinded randomized controlled trial (RCT) with three parallel groups in La Réunion Island, a region where metabolic diseases are highly prevalent.

SUBJECTS

One hundred and thirty-six non-diabetic obese (body mass index [BMI]: 27-40 kg/m2) young women (aged 20-40) were randomized (G1: MFO intensity; G2: 60% of VO2-peak intensity; G3: free moderate-intensity at-home exercise following good physical practices).

OUTCOMES

Anthropometry (BMI, bodyweight, FM, fat-free mass), glucose (fasting plasma glucose, insulin, HOMA-IR) and lipid (cholesterol and triglycerides) profiles, and MFO values were measured at month-0, month-3 and month-5.

RESULTS

At month-5, among 109 women assessed on body composition, the three groups exhibited a significant FM reduction over time (G1: -4.1±0.54 kg; G2: -4.7±0.53 kg; G3: -3.5±0.78 kg, p<0.001, respectively) without inter-group differences (p = 0.135). All groups exhibited significant reductions in insulin levels or HOMA-IR index, and higher MFO values over time (p<0.001, respectively) but glucose control improvement was higher in G1 than in G3 while MFO values were higher in G1 than in G2 and G3. Changes in other outcome measures and inter-group differences were not significant.

CONCLUSION

In our RCT the LIPOXmax intervention did not show a superiority in reducing FM in overweight or obese women but is associated with higher MFO and better glucose control improvements. Other studies are required before proposing LIPOXmax training for the prevention of T2DM in overweight or obese women.

TRIAL REGISTRATION

ClincialTrials.gov NCT01464073.

Exercise training at the maximal fat oxidation intensity improved health-related physical fitness in overweight middle-aged women

Background/Objective

The purpose of this study was to test the hypothesis that exercise training at the maximal fat oxidation (FATmax) intensity would improve the health-related physical fitness in overweight middle-aged women.

Methods

Thirty women (45-59 years old and BMI 28.2 ± 1.8 kg/m²) were randomly allocated into the Exercise and Control groups. Body composition, FATmax, predicted maximal oxygen uptake, heart function during submaximal exercise, stroke volume, left ventricular ejection fraction, trunk muscle strength, and body flexibility were measured before and after the experimental period.

Results

Following the 10 weeks of supervised exercise training, the Exercise group achieved significant improvements in body composition, cardiovascular function, skeletal muscle strength, and body flexibility; whereas there were no changes in these variables of the Control group. There was also no significant change in daily energy intake for all participants before and after the interventions.

Conclusion

The 10-week FATmax intensity training is an effective treatment to improve health-related physical fitness in overweight middle-aged women.

Short-term HIIT and Fat max training increase aerobic and metabolic fitness in men with class II and III obesity

OBJECTIVE

To compare the effects of two different 2-week-long training modalities [continuous at the intensity eliciting the maximal fat oxidation (Fatmax) versus high-intensity interval training (HIIT)] in men with class II and III obesity.

METHODS

Nineteen men with obesity (BMI ≥ 35 kg · m(-2)) were assigned to Fatmax group (GFatmax) or to HIIT group (GHIIT). Both groups performed eight cycling sessions matched for mechanical work. Aerobic fitness and fat oxidation rates (FORs) during exercise were assessed prior and following the training. Blood samples were drawn to determine hormones and plasma metabolites levels. Insulin resistance was assessed by the homeostasis model assessment of insulin resistance (HOMA2-IR).

RESULTS

Aerobic fitness and FORs during exercise were significantly increased in both groups after training (P ≤ 0.001). HOMA2-IR was significantly reduced only for GFatmax (P ≤ 0.001). Resting non-esterified fatty acids (NEFA) and insulin decreased significantly only in GFatmax (P ≤ 0.002).

CONCLUSIONS

Two weeks of HIIT and Fatmax training are effective for the improvement of aerobic fitness and FORs during exercise in these classes of obesity. The decreased levels of resting NEFA only in GFatmax may be involved in the decreased insulin resistance only in this group.

Maximal Fat Oxidation Rate during Exercise in Korean Women with Type 2 Diabetes Mellitus

BACKGROUND

The purpose of this study was to determine the appropriate exercise intensity associated with maximum fat oxidation, improvement of body composition, and metabolic status in Korean women with type 2 diabetes mellitus (T2DM).

METHODS

The study included a T2DM group (12 women) and a control group (12 women). The groups were matched in age and body mass index. The subjects performed a graded exercise test on a cycle ergometer to measure their maximal fat oxidation (Fatmax). We also measured their body composition, metabolic profiles, and mitochondrial DNA (mtDNA).

RESULTS

The exercise intensity for Fatmax was significantly lower in the T2DM group (34.19% maximal oxygen uptake [VO2 max]) than the control group (51.80% VO2 max). Additionally, the rate of fat oxidation during exercise (P<0.05) and mtDNA (P<0.05) were significantly lower in the T2DM group than the control group. The VO2 max level (P<0.001) and the insulin level (P<0.05) were positively correlated with the rate of fat oxidation.

CONCLUSION

The results of this study suggest lower exercise intensity that achieves Fatmax is recommended for improving fat oxidation and enhancing fitness levels in Korean women with T2DM. Our data could be useful when considering an exercise regimen to improve health and fitness.

Objectively measured sedentary time and associations with insulin sensitivity: Importance of reallocating sedentary time to physical activity

OBJECTIVE

The aim of this study is to quantify associations between objectively measured sedentary time and markers of insulin sensitivity by considering allocation into light-intensity physical activity or moderate- to vigorous-intensity physical activity (MVPA).

METHODS

Participants with an increased risk of impaired glucose regulation (IGR) were recruited (Leicestershire, United Kingdom, 2010-2011). Sedentary, light-intensity physical activity and MVPA time were measured using accelerometers. Fasting and 2-hour post-challenge insulin and glucose were assessed; insulin sensitivity was calculated by HOMA-IS and Matsuda-ISI. Isotemporal substitution regression models were used. Data were analysed in 2014.

RESULTS

508 participants were included (average age=65years, female=34%). Reallocating 30min of sedentary time into light-intensity physical activity was associated a 5% (95% CI 1, 9%; p=0.024) difference in Matsuda-ISI after adjustment for measured confounding variables. Reallocation into MVPA was associated with a 15% (7, 25%; p<0.001) difference in HOMA-IS and 18% (8, 28%; p<0.001) difference in Matsuda-ISI. Results for light-intensity physical activity were modified by IGR status with stronger associations seen in those with IGR.

CONCLUSIONS

Reallocating sedentary time into light-intensity physical activity or MVPA was associated with differences in insulin sensitivity, with stronger and more consistent associations seen for MVPA.

Aerobic and resistance exercise training program intervention for enhancing gait function in elderly and chronically ill Taiwanese patients

OBJECTIVES

This study aimed to develop an effective exercise training program for enhancing the postural stability and gait function of chronically ill patients to avoid falls.

STUDY DESIGN

Pre training-post-training. Analyses were limited to those randomized to the exercise intervention.

METHODS

The participants were chronically ill patients over 45 years old (47-89 years), of whom 25 completed the 12-week training regimen and assessment in the exercise group, whereas 29 completed the assessment in the control group, suffering from cardiovascular disease, diabetes mellitus, or osteoporosis. The average age of the participants was 67.56 ± 10.70 years in the intervention group. All patients in this study signed institutional review board (IRB) agreements before participating (IRB approval no: FEMH-IRB-101029-E, v. 02, date: 20120429).

RESULTS

The results revealed the beneficial effects of regular aerobic and resistance training, which improved in elderly, chronically ill patients. According to our data, most of the gait function measurements exhibited significant differences between the exercise group and control group. The duration of the 'timed up-and-go' test decreased from 7.67 s to 6.76 s (P = 0.00013), and the 'the base of support area' increased from 392.0 cm(2) to 433.2 cm(2) (P = 0.0088). Women attained more significant differences than men in the exercise and control groups (P = 0.0008), and the participants aged 45-65 years had a more satisfactory outcome than those aged > 65 years (P = 0.0109).

CONCLUSION

Regular exercise regimens, such as aerobic, resistance or combination exercise training, enhance the gait function and sense of postural stability in elderly, chronically ill patients. Younger patients attained more positive results than older patients, and women attained more positive results than men. Regular exercise is a means of preventing falls; thus, the government and hospitals should increase promotional measures in aging communities to encourage regular exercise among elderly, chronically ill outpatients.

Effects of Endurance Training at the Crossover Point in Women with Metabolic Syndrome

INTRODUCTION

On the basis of theoretical evidence, intensity at the crossover point (COP) of substrate utilization could be considered as potential exercise intensity for metabolic syndrome (MetS). This study aimed to examine the effects of a training program at COP on exercise capacity parameters in women with MetS and to compare two metabolic indices (COP and the maximal fat oxidation rate point LIPOXmax®) with ventilatory threshold (VT).

METHODS

Nineteen women with MetS volunteered to perform a 12-wk training program on a cycle ergometer, with intensity corresponding to COP. Pre- and posttraining values of anthropometric and exercise capacity parameters were compared to determine the effects of exercise training. The pre-post training change of COP, LIPOXmax®, and VT were also investigated.

RESULTS

After training, anthropometric parameters were significantly modified, with reduction of body mass (3.0% ± 3.0%, P < 0.001), fat mass (3.3% ± 3.4%, P < 0.001), and body mass index (3.2% ± 3.4%, P < 0.001). Exercise capacity was improved after the training program, with significant increase of maximal power output (25.0% ± 18.4%, P < 0.001) and maximal oxygen uptake (V˙O2max, 9.0% ± 11.2%; P < 0.01). Lastly, when expressed in terms of power output, COP, LIPOXmax®, and VT occurred at a similar exercise intensity, but the occurrence of these three indices is different when expressed in terms of oxygen uptake, HR, or RPE.

CONCLUSIONS

This study highlights the effectiveness of a 12-wk training program at COP to improve physical fitness in women with MetS. The relations between metabolic indices and VT in terms of power output highlight the determination of VT from a shorter maximal exercise as a useful method for determining metabolic indices in MetS.

Improvement of pulmonary function with arm swing exercise in patients with type 2 diabetes

[Purpose] Obesity and hyperglycemia play roles in the impairment of pulmonary function in type 2 diabetes mellitus (T2DM) patients. Low-intensity exercise is known to reduce body fat and improve hyperglycemia. The arm swing exercise (ASE), a low-intensity exercise, is easy and convenient to perform without any equipment and is suitable for daily practice. Therefore, we aimed to investigate the effects of ASE on lung function and obesity in overweight T2DM patients. [Subjects and Methods] Twenty-four subjects continued their daily life routines for 8 weeks (control period), and then performed ASE for 8 weeks (30 minutes per day, 3 days per week) (ASE period). Pulmonary function tests were performed, and fasting blood glucose, haemoglobin A1c (HbA1c), lipid profiles, high-sensitive C-reactive protein (HSCRP), insulin concentration, and anthropometric parameters were measured before and after each period. [Results] After the ASE period, the forced vital capacity, forced expiratory volume in the first second of expiration, and maximal voluntary ventilation were increased when compared with after the control period. HbA1c, a low-density lipoprotein, malondialdehyde, oxidized glutathione, and the percent body fat were significantly decreased when compared with after the control period. However, other parameters, such as lung volume, anthropometric parameters, and fasting blood glucose, insulin, high-density lipoprotein, triglycerides, total cholesterol and glutathione concentrations, showed no differences between the two periods. [Conclusion] These data suggest that there is improvement of pulmonary functions in T2DM patients after ASE training.

The effects of exercise training on the traditional lipid profile and beyond

The purpose of this review is to provide up-to-date information regarding the effects of aerobic and resistance exercise training on the traditional blood lipid and lipoprotein profile. In addition, emerging coronary artery disease (CAD) risk factors, such as postprandial lipemia (PPL) and metabolic syndrome (MetS), are reviewed. Numerous studies report that aerobic exercise combined with weight loss significantly reduces blood cholesterol, low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), and triglycerides (TG) while improving high-density lipoprotein cholesterol (HDL-C). Both aerobic and resistance training demonstrated a reduction in non-HDL-C independent of changes in body weight. Transient beneficial effects of a single session of aerobic exercise are observed for PPL. Nonetheless further research is needed to provide a better understanding of the potential mechanisms for reducing PPL. Exercise as an intervention for patients with MetS leads to improved CAD risk factors including atherogenic dyslipidemia, blood pressure, body composition, insulin sensitivity, and fat metabolism.

Rheumatoid cachexia revisited: a metabolic co-morbidity in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which pro-inflammatory cytokines, including tumor necrosis factor (TNF)-α, play a crucial role. The chronic inflammation, combined with reduced physical activity, leads to muscle wasting whereas fat mass would be maintained; the resulting abnormal metabolic state is described as rheumatoid cachexia. Since the loss of muscle volume would be compensated by the increased fat mass, body mass index (BMI) is reported not to reflect the nutritional status in RA patients. The implication of rheumatoid cachexia for cardiovascular risk and clinical prognosis is not clearly understood, however, adequate control of disease activity in combination with appropriate physical exercise could be the most important strategy to control rheumatoid cachexia and related metabolic problems.

Positive effect of exercise training at maximal fat oxidation intensity on body composition and lipid metabolism in overweight middle-aged women

The purpose of this study was to test the hypothesis that 10 weeks of supervised exercise training at the maximal fat oxidation (FATmax) intensity would improve important variables of body composition and lipid metabolism in overweight middle-aged women. A longitudinal study design was employed to evaluate the effects of FATmax exercise training. Thirty women (45-59 years old; BMI 28·2 ± 1·8 kg m(-2) ; body fat 38·9 ± 4·1%) were randomly allocated into the Exercise and Control groups, n = 15 in each group. Body composition, FATmax, predicted VO2 max, lipid profile, plasma lipoprotein lipase activity and serum leptin concentration were measured before and after the experimental period. The Exercise group was trained at the individualized FATmax intensity, 5 days per week and 1 h per day for 10 weeks. No diet control was introduced during the experimental period for all participants. Exercise group obtained significant decreases in body mass, BMI, body fat % and abdominal fat mass, as well as the concentrations of triglycerides, serum leptin and blood glucose. The activity of lipoprotein lipase was increased in trained participants. There were no changes in these variables in the Control group. In addition, there was no significant change in daily energy intake for all participants before and after the experimental period. In conclusion, the 10-week FATmax exercise training achieved improvements in body composition and lipid metabolism in overweight middle-aged women. This result suggests FATmax is an effective exercise training intensity for obesity treatment.

Reproducibility of Fatmax and fat oxidation rates during exercise in recreationally trained males

Aerobic exercise training performed at the intensity eliciting maximal fat oxidation (Fat(max)) has been shown to improve the metabolic profile of obese patients. However, limited information is available on the reproducibility of Fat(max) and related physiological measures. The aim of this study was to assess the intra-individual variability of: a) Fat(max) measurements determined using three different data analysis approaches and b) fat and carbohydrate oxidation rates at rest and at each stage of an individualized graded test. Fifteen healthy males [body mass index 23.1 ± 0.6 kg/m(2), maximal oxygen consumption (VO2max) 52.0 ± 2.0 ml/kg/min] completed a maximal test and two identical submaximal incremental tests on ergocycle (30-min rest followed by 5-min stages with increments of 7.5% of the maximal power output). Fat and carbohydrate oxidation rates were determined using indirect calorimetry. Fat(max) was determined with three approaches: the sine model (SIN), measured values (MV) and 3rd polynomial curve (P3). Intra-individual coefficients of variation (CVs) and limits of agreement were calculated. CV for Fat(max) determined with SIN was 16.4% and tended to be lower than with P3 and MV (18.6% and 20.8%, respectively). Limits of agreement for Fat(max) were -2 ± 27% of VO2max with SIN, -4 ± 32 with P3 and -4 ± 28 with MV. CVs of oxygen uptake, carbon dioxide production and respiratory exchange rate were <10% at rest and <5% during exercise. Conversely, CVs of fat oxidation rates (20% at rest and 24-49% during exercise) and carbohydrate oxidation rates (33.5% at rest, 8.5-12.9% during exercise) were higher. The intra-individual variability of Fat(max) and fat oxidation rates was high (CV>15%), regardless of the data analysis approach employed. Further research on the determinants of the variability of Fat(max) and fat oxidation rates is required.

Effect of an IT-supported home-based exercise programme on metabolic syndrome in India

Summary

We studied the effectiveness of a home-based exercise programme with information technology (IT) support in people with metabolic syndrome in India. Ninety-four participants with metabolic syndrome (mean age 50 years) were randomized into two groups. Both groups received a 12-week home exercise programme and Group 2 received additional IT support for health education. Before and after the exercise programme, participants were measured for arterial stiffness using applanation tonometry, exercise capacity using an incremental shuttle walk test and quality of life (QoL) using the SF-36 questionnaire. Sixty-one participants completed the post intervention tests. There was a significant reduction in systolic blood pressure, mean pressure and aortic systolic pressure in both groups. Pulse wave velocity, aortic pulse pressure and aortic diastolic pressure showed significant reductions only in Group 2. There were no significant changes in QoL measures, except vitality in Group 2. There was significant improvement in fasting blood glucose in Group 2, cholesterol in Group 1 and triglycerides in both groups. The participants’ exercise capacity did not change significantly, although the mean duration of regular exercise was 7.2 weeks for Group 1 and 10.0 weeks for Group 2 ( P = 0.019). Metabolic syndrome was reversed in 16% of the participants in both groups. IT support, through mobile text messages and phone calls, may be helpful in metabolic syndrome. Longer-term studies are now required.

Comparison of glucose tolerance tests to detect the insulin sensitizing effects of a bout of continuous exercise

The aim of the present study was to determine which of the available glucose tolerance tests (oral (OGTT) vs. intravenous (IVGTT)) could more readily detect the insulin sensitizing effects of a bout of continuous exercise. Ten healthy moderately fit young men (V̇O2peak of 45.4 ± 1.8 mL·kg(-1)·min(-1); age 27.5 ± 2.7 yr) underwent 4 OGTT and 4 IVGTT on different days following a standardized dinner and overnight fast. One test was performed immediately after 55 min of cycle-ergometer exercise at 60% V̇O2peak. Insulin sensitivity index was determined during a 50 min IVGTT according to Tura (CISI) and from a 120 min OGTT using the Matsuda composite index (MISI). After exercise, MISI improved 29 ± 10% without reaching statistical significance (p = 0.182) due to its low reproducibility (coefficient of variation 16 ± 3%; intra-class reliability 0.846). However, CISI significantly improved (50 ± 4%; p < 0.001) after exercise showing better reproducibility (coefficient of variation 13 ± 4%; intra-class reliability 0.955). Power calculation revealed that 6 participants were required for detecting the effects of exercise on insulin sensitivity when using IVGTT, whereas 54 were needed when using OGTT. The superior response of CISI compared with MISI suggests the preferential use of IVGTT to assess the effects of exercise on insulin sensitivity when using a glucose tolerance test.