Lipid oxidation in overweight men after exercise and food intake

Influence of Acute and Chronic Exercise on Abdominal Fat Lipolysis: An Update

Exercise is a powerful and effective preventive measure against chronic diseases by increasing energy expenditure and substrate mobilization. Long-duration acute exercise favors lipid mobilization from adipose tissue, i.e., lipolysis, as well as lipid oxidation by skeletal muscles, while chronic endurance exercise improves body composition, facilitates diet-induced weight loss and long-term weight maintenance. Several hormones and factors have been shown to stimulate lipolysis in vitro in isolated adipocytes. Our current knowledge supports the view that catecholamines, atrial natriuretic peptide and insulin are the main physiological stimuli of exercise-induced lipolysis in humans. Emerging evidences indicate that contracting skeletal muscle can release substances capable of remote signaling to organs during exercise. This fascinating crosstalk between skeletal muscle and adipose tissue during exercise is currently challenging our classical view of the physiological control of lipolysis, and provides a conceptual framework to better understand the pleotropic benefits of exercise at the whole-body level.

Effect of High-Intensity Interval Training Versus Moderate-Intensity Aerobic Continuous Training on Galectin-3 Gene Expression in Postmenopausal Women: A Randomized Controlled Trial

Galectin-3 is a pro-inflammatory biomarker associated with the pathogenesis of heart failure (HF). Physical-activity reduces the risk of heart-failure by modification of inflammation and fibrosis. The purpose of this study was to compare the effects of 8 weeks of high-intensity interval training (HIIT) versus moderate-intensity aerobic continuous training on a predictive factor of HF in postmenopausal women. Thirty sedentary postmenopausal women were randomly assigned to three groups. The first group performed the HIIT program at 60%-90%, and the second group performed an exercise program at 50%-65% of HR reserve. The control group maintained their normal daily regular physical activity level. The gene expressions of galectin-3 and lipid profiles were measured at the baseline and the end of Week 8. The HIIT and moderate-intensity aerobic continuous training attenuated the gene expression of galectin-3, serum low-density lipoprotein, cholesterol, and triglyceride concentrations and enhanced high-density lipoprotein concentrations. These changes were considerably higher in the HIIT group. Our results show that HIIT is superior to moderate-intensity aerobic continuous training in improving the decrease in HF risk in postmenopausal women.

Acute exercise effects on postprandial fat oxidation: meta-analysis and systematic review

The purpose of this systematic review was to synthesize and evaluate current literature examining the effects of exercise on postprandial fat oxidation, as well as to provide future direction. A quantitative review was performed using meta-analytic methods. A moderator analysis was performed to investigate potential variables that could influence the effect of exercise on postprandial fat oxidation. Fifty-six effects from 26 studies were retrieved. There was a moderate effect of exercise on postprandial fat oxidation (Cohen's d = 0.58 (95% CI, 0.39 to 0.78)). Moderator analysis revealed that sex, age, weight status, training status, exercise type, exercise intensity, timing of exercise, and composition of the meal challenge significantly affected the impact of prior exercise on postprandial fat oxidation. The moderator analysis also indicated that most previous studies have investigated the impact of prior moderate-intensity endurance exercise on postprandial fat oxidation in young, healthy, lean men. Suggested priorities for future research in this area include (i) an examination of sex differences in and/or female-specific aspects of postprandial metabolism; (ii) a comprehensive evaluation of exercise modalities, intensities, and durations; and (iii) a wider variety of test meal compositions, especially those with higher fat content. Novelty A systematic review of the impact of exercise on postprandial fat oxidation was performed using meta-analytic methods. Analysis revealed a moderate effect of exercise on postprandial fat oxidation. The presented data support a need for future studies to investigate sex differences and to include comprehensive evaluations of exercise modalities, intensities, and duration.

Metabolomics approach to investigate the ergogenic effect of Morinda citrifolia L. leaf extract on obese Sprague Dawley rats

INTRODUCTION

Natural products are obtaining much acceptance as ergogenic aid, not only among athletes but also among the general population including people with excess body fat. Under normal circumstances, an obese person will have the desire and ability to exercise reduced; mainly because they are easily fatigued. Thus, they need to boost their energy production so that they can be more active and healthier.

OBJECTIVE

In this present work, Morinda citrifolia L. leaf extract (MLE) which is believed to possess ergogenic property, was evaluated on its effect on an obese animal model using ¹ H-NMR based metabolomics.

MATERIAL AND METHODS

Rats were fed with high fat diet (HFD) for 12 weeks for obese development. Once this was achieved, all the rats underwent endurance exercise (forced swimming test) every 2 weeks for 8 weeks together with treatment. The time to exhaustion was recorded for each rat. Three different dosages of MLE: 50 mg/kg, 100 mg/kg and 200 mg/kg of body weight were used together with two positive controls: 5 mg/kg caffeine and 100 mg/kg green tea. Blood was collected before and after treatments for metabolomics study.

RESULTS

Findings showed that feeding the rats at a dose of 200 mg/kg body weight MLE significantly prolonged the exhaustive swimming time of the rats, and altered the metabolites present in their serum. Discriminating metabolites involved were the product of various metabolic pathways, including carbohydrate, lipids metabolism and energy metabolism. Treatment with 200 mg/kg body weight MLE resulted in significant improvement in the metabolic perturbations where the proximity of the obese exercised treated group to that of normal exercised group in the partial least squares discriminant analysis score plot was observed.

CONCLUSION

The present work demonstrated ergogenic property of MLE based on the improved metabolic perturbation in exercised obese rats.

Influence of upper-body continuous, resistance or high-intensity interval training (CRIT) on postprandial responses in persons with spinal cord injury: study protocol for a randomised controlled trial

Background

Chronic spinal cord injury (SCI) increases morbidity and mortality associated with cardiometabolic diseases, secondary to increases in central adiposity, hyperlipidaemia and impaired glucose tolerance. While upper-body Moderate Intensity Continuous Training (MICT) improves cardiorespiratory fitness, its effects on cardiometabolic component risks in adults with SCI appear relatively modest. The aim of this study is to assess the acute effects of Continuous Resistance Training (CRT), High Intensity Interval Training (HIIT), MICT and rest (CON) on fasting and postprandial systemic biomarkers and substrate utilisation.

Methods

Eleven healthy, chronic SCI (> 1 year, ASIA A-C) men will be recruited. Following preliminary testing, each will complete four experimental conditions, where they will report to the laboratory following an ~ 10-h overnight fast. A venous blood sample will be drawn and expired gases collected to estimate resting metabolic rate (RMR). In order to ensure an isocaloric exercise challenge, each will complete CRT first, with the remaining three conditions presented in randomised order: (1) CRT, ~ 45 min of resistance manoeuvres (weight lifting) interspersed with low-resistance, high-speed arm-crank exercise; (2) CON, seated rest; (3) MICT, ~ 45 min constant arm-crank exercise at a resistance equivalent to 30–40% peak power output (PPO) and; (4) HIIT, ~ 35 min arm-crank exercise with the resistance alternating every 2 min between 10% PPO and 70% PPO. After each ~ 45-min condition, participants will ingest a 2510-kJ liquid test meal (35% fat, 50% carbohydrate, 15% protein). Venous blood and expired gas samples will be collected at the end of exercise and at regular intervals for 120 min post meal.

Discussion

This study should establish the acute effects of different forms of exercise on fasting and postprandial responses in chronic SCI male patients. Measures of glucose clearance, insulin sensitivity, lipid and inflammatory biomarker concentrations will be assessed and changes in whole-body substrate oxidation estimated from expired gases.

Trial registration

ClinicalTrials.gov, ID: NCT03545867. Retrospectively registered on 1 June 2018. 

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3583-1) contains supplementary material, which is available to authorized users.

Comparison of energy-matched high-intensity interval and moderate-intensity continuous exercise sessions on latency to eat, energy intake, and appetite

High-intensity interval exercises (HIIex) have gained popularity but their effects on eating behavior are poorly known. The aim of this study was to evaluate whether the effects of HIIex on the 3 main components of eating behavior (appetite, intake, and latency to eat) differ from those of moderate-intensity continuous exercises (MICex) for the same energy expenditure. Fifteen young normal-weight males completed 3 sessions in a counterbalanced order: HIIex (30-s bouts at 90% of maximal oxygen uptake interceded with 60-s bouts at 35% of maximal oxygen uptake for 20 min), MICex (42% of maximal oxygen uptake for 40 min), and a resting session (REST). Trials were scheduled 80 and 100 min after a standard breakfast for MICex and HIIex, respectively. At 120 min, participants were isolated until they asked for lunch. Appetite was rated on 4 visual analog scales (hunger, desire to eat, fullness, and prospective consumption) every 15 min until meal request. Results showed that the mean latency of requesting lunch was significantly longer after HIIex than after REST (+17.3 ± 4.3 min, P = 0.004), but not after MICex (P = 0.686). Energy intake was not different between conditions, leading to a negative energy balance in the 2 exercise sessions. Thus, the effects of HIIex on eating behavior are likely primarily mediated through the latency of meal initiation. However, inter-individual variability was large and further studies are needed to identify the predictive factors of this response.

The effects of either resveratrol or exercise on macrophage infiltration and switching from M1 to M2 in high fat diet mice

PURPOSE

The aim of this study was to compare the effectiveness of either resveratrol supplementation or exercise training on macrophage infiltration and switching from M1 to M2 kupffer cells in high fat diet mice.

METHODS

C57BL/6 mice were separated into 5 groups: normal diet (ND; n = 6), high-fat diet (HD; n = 6), high-fat diet with resveratrol (HR; n = 6), high-fat diet with exercise (HE; n = 6) or high-fat diet with resveratrol and exercise (HRE; n = 6). Resveratrol supplementation mice were orally gavaged with resveratrol (25mg/kg of body weight) dissolved in 50% propylene glycol. Exercise mice ran on a treadmill at 12-20 m/min for 30-60 min/day, 5 times/week for 12 weeks.

RESULTS

After 12 weeks of intervention, the liver was analyzed. F4/80 expression was evaluated by western blot while CD11c and CD163 mRNA expressions were evaluated by RT-PCR. The weights of the body and liver were significantly increased in the HD and HR group compared to the ND group (p < 0.01). However, the weights were most effectively reduced in the HE and HRE groups compared to the HD group (p < 0.05). The macrophage marker, F4/80 expression was significantly lower in the HE and HRE groups compared to the HD group (p < 0.05). mRNA expression of the M1 macrophage marker, CD11c, in the HD group was significantly increased compared to the ND group (p < 0.01). mRNA expression of the M2 macrophage specific marker, CD163, in the HE and HRE groups were significantly increased compared to the HD group (p < 0.05). The mRNA expressions of TLR4, ICAM-1 and VCAM-1, which induce pro-inflammatory cytokine production, were strongly decreased in the HR, HE, and HRE groups compared to the HD group.

CONCLUSION

These results suggest that moderate exercise training inhibits macrophage infiltration and up regulation of CD163 expression. However, resveratrol supplementation is not enough to ameliorate obesity-induced macrophage infiltration and switching.

Determinants of resting lipid oxidation in response to a prior bout of endurance exercise

A single bout of exercise can alter subsequent resting metabolism for many hours and into the next day. However, differences between men and women, effects of nutritional state, and relative effects of resting metabolic rate (RMR) and respiratory exchange ratio (RER) in controlling the increase in lipid oxidation (Lox) after exercise are not yet clear. Effects of aerobic capacity (Vo2 peak) and exercise bout parameters (intensity and volume) also remain to be clearly elucidated as does the time course of changes after exercise. We performed a meta-analysis to assess these potential moderators of the impact of endurance exercise [effect sizes (ESs)] on subsequent Lox at rest (ES = 0.91; 95% CI: 0.69-1.12), on the day of exercise (ES = 1.22; 95% CI: 0.89-1.55), and on the following day (ES = 0.60; 95% CI: 0.35-0.85). ES for the exercise-related increase in resting Lox was significantly greater in men than women in the postabsorptive state but similar in the postprandial state. The ES for depression of RER after exercise was similar between men and women, while the ES for RMR in the postabsorptive state tended to be higher in men than women. Finally, Vo2 peak and exercise energy expenditure (EEE), but not intensity, were predictive of postexercise Lox. The findings indicate importance of EEE and fitness for ability to achieve robust enhancement of Lox after exercise. The results additionally indicate a gender difference in postexercise Lox that is dependent on nutritional state, as the ES for Lox was lower in women only in the postabsorptive state.

Effect of interval training intensity on fat oxidation, blood lactate and the rate of perceived exertion in obese men

PURPOSE

The objectives of this study were to examine the effect of 4-week moderate- and high-intensity interval training (MIIT and HIIT) on fat oxidation and the responses of blood lactate (BLa) and rating of perceived exertion (RPE).

METHODS

Ten overweight/obese men (age = 29 ±3.7 years, BMI = 30.7 ±3.4 kg/m(2)) participated in a cross-over study of 4-week MIIT and HIIT training. The MIIT training sessions consisted of 5-min cycling stages at mechanical workloads 20% above and 20% below 45%VO2peak. The HIIT sessions consisted of intervals of 30-s work at 90%VO2peak and 30-s rest. Pre- and post-training assessments included VO2max using a graded exercise test (GXT) and fat oxidation using a 45-min constant-load test at 45%VO2max. BLa and RPE were also measured during the constant-load exercise test.

RESULTS

There were no significant changes in body composition with either intervention. There were significant increases in fat oxidation after MIIT and HIIT (p ≤ 0.01), with no effect of intensity. BLa during the constant-load exercise test significantly decreased after MIIT and HIIT (p ≤ 0.01), and the difference between MIIT and HIIT was not significant (p = 0.09). RPE significantly decreased after HIIT greater than MIIT (p ≤ 0.05).

CONCLUSION

Interval training can increase fat oxidation with no effect of exercise intensity, but BLa and RPE decreased after HIIT to greater extent than MIIT.

Effect of endurance training on skeletal muscle myokine expression in obese men: identification of apelin as a novel myokine

BACKGROUND

It has been suggested that the metabolic benefits of physical exercise could be mediated by myokines. We examined here the effect of exercise training on skeletal muscle expression of a panel of myokines in humans. Pathways regulating myokine expression were investigated in human myotubes.

METHODS

Eleven obese non-diabetic male subjects were enrolled in an 8-week endurance training program. Insulin sensitivity was assessed by an oral glucose tolerance test. Subcutaneous adipose tissue and Vastus lateralis muscle biopsy samples were collected before and after training. RNAs were prepared from adipose tissue and skeletal muscle. Primary culture of myoblasts was established.

RESULTS

As expected, exercise training improved aerobic capacity and decreased fat mass. No significant change in interleukin 6, fibroblast growth factor 21, myostatin (MSTN) or irisin mRNA level was found in muscle after training. A twofold increase in apelin mRNA level was found in muscle but not in adipose tissue. No change in circulating myokine and adipokine plasma levels was observed in the resting state in response to training. Interestingly, apelin was significantly expressed and secreted in primary human myotubes. Apelin gene expression was upregulated by cyclic AMP and calcium, unlike the other myokines investigated. Importantly, changes in muscle apelin mRNA levels were positively related to whole-body insulin sensitivity improvement.

CONCLUSION

Collectively, our data show that exercise training upregulates muscle apelin expression in obese subjects. Apelin expression is induced by exercise signaling pathways and secreted in vitro in human primary myotubes, and may behave as a novel exercise-regulated myokine with autocrine/paracrine action.

Metabolic and hormonal consequences of two different meals after a moderate intensity exercise bout in obese prepubertal children

BACKGROUND/OBJECTIVES

To investigate the relationship between postprandial nutrient balance, satiety and hormone changes induced by two different meals taken after a moderate intensity exercise bout.

SUBJECTS/METHODS

Ten prepubertal obese children participated in the study. The experiment was designed as a cross-over study for repeated measures. Each test period lasted five consecutive hours during which the children were under medical supervision. The effects of two isocaloric meals were compared after a moderate intensity exercise (4 multiples of resting metabolic rate, 30 min, cycling): a low-fat/high-carbohydrate meal (meal A) and a high-fat/low-carbohydrate meal (meal B). Pre and postprandial (3 h) substrate oxidation, biochemical parameters, gastrointestinal hormone concentrations and appetite were measured.

RESULTS

The main results were: (i) higher fat balance (5.1±5.0 vs -5.0±6.6 g, P=0.001) and lower carbohydrate balance after meal B than A (-9.7±13.3 vs 11.3±18.3 g, P<0.01); (ii) higher energy balance after meal B than after meal A (5.9±21.5 vs -13.9±20.2 kcal, P<0.05); (iii) higher plasma triglyceride concentrations (area under the curve) after meal B than after meal A (2962.5±2095.8 mg*180 min/dl vs -169.5±1633.7 mg*180 min/dl, P<0.01); (iv) higher serum glucagon-like peptide-1 concentrations after meal B than after meal A (1101.5±873.0 pmol*180 min/l vs 478.8±638.3 pmol*180 min/l, P<0.05).

CONCLUSIONS

After a bout of moderate intensity exercise, a meal with a high-fat/low-carbohydrate ratio had a less favorable metabolic impact than an isoenergetic, isoproteic low-fat/high-carbohydrate meal.