Understanding the factors that effect maximal fat oxidation

Factors Determining the Agreement between Aerobic Threshold and Point of Maximal Fat Oxidation: Follow-Up on a Systematic Review and Meta-Analysis on Association

Regular exercise at the intensity matching maximal fat oxidation (FATmax) has been proposed as a key element in both athletes and clinical populations when aiming to enhance the body's ability to oxidize fat. In order to allow a more standardized and tailored training approach, the connection between FATmax and the individual aerobic thresholds (AerT) has been examined. Although recent findings strongly suggest that a relationship exists between these two intensities, correlation alone is not sufficient to confirm that the intensities necessarily coincide and that the error between the two measures is small. Thus, this systematic review and meta-analysis aim to examine the agreement levels between the exercise intensities matching FATmax and AerT by pooling limits of agreement in a function of three parameters: (i) the average difference, (ii) the average within-study variation, and (iii) the variation in bias across studies, and to examine the influence of clinical and methodological inter- and intra-study differences on agreement levels. This study was registered with PROSPERO (CRD42021239351) and ClinicalTrials (NCT03789045). PubMed and Google Scholar were searched for studies examining FATmax and AerT connection. Overall, 12 studies with forty-five effect sizes and a total of 774 subjects fulfilled the inclusion criteria. The ROBIS tool for risk of bias assessment was used to determine the quality of included studies. In conclusion, the overall 95% limits of agreement of the differences between FATmax and AerT exercise intensities were larger than the a priori determined acceptable agreement due to the large variance caused by clinical and methodological differences among the studies. Therefore, we recommend that future studies follow a strict standardization of data collection and analysis of FATmax- and AerT-related outcomes.

Comparison of Metabolic Characteristics of Physically Active Individuals with Different Training Habits during Incremental Treadmill Test

The number of people engaging in self-conducted regular physical activity is increasing, but the effects of home fitness and individually planned workouts on health and metabolism are unknown. We aimed to examine the effects of regular training conducted without the supervision of professionals on exercise metabolism in our cross-sectional observational study. Forty-five physically active volunteers, classified into three groups, based on the type and frequency of their training (group 1 frequent long-term endurance, group 2 three times per week aerobic training, and group 3 two times per week short aerobic and resistance training), fulfilled a vita maxima incremental treadmill test. Aerobic capacity (VO2max), MET (metabolic equivalent of task), and metabolic responses were examined. The results were evaluated by ANOVA and Bonferroni and Scheffe multiple comparison analysis using Microsoft Excel and SPSS 23 programs. (p < 0.05). Significant differences were found between group 1 and 3 in VO2max (p = 0.46) and MET (p = 0.46) between group 1 and 2, in FatmaxHR (heart rate on maximum fat oxidation) (p= 0.04). We concluded self-conducted regular physical activity has positive effects on metabolism and health. Aerobic training performed four times per week showed the most beneficial effects on metabolism and health maintenance. In addition, based on our findings, strength training performed two times per week is recommended.

Low-carbohydrate diets and men's cortisol and testosterone: Systematic review and meta-analysis

Background: Low-carbohydrate diets may have endocrine effects, although individual studies are conflicting. Therefore, a review was conducted on the effects of low- versus high-carbohydrate diets on men's testosterone and cortisol. Methods: The review was registered on PROSPERO (CRD42021255957). The inclusion criteria were: intervention study, healthy adult males, and low-carbohydrate diet: ≤35% carbohydrate. Eight databases were searched from conception to May 2021. Cochrane's risk of bias tool was used for quality assessment. Random-effects, meta-analyses using standardized mean differences and 95% confidence intervals, were performed with Review Manager. Subgroup analyses were conducted for diet duration, protein intake, and exercise duration. Results: Twenty-seven studies were included, with a total of 309 participants. Short-term (<3 weeks), low- versus high-carbohydrate diets moderately increased resting cortisol (0.41 [0.16, 0.66], p < 0.01). Whereas, long-term (≥3 weeks), low-carbohydrate diets had no consistent effect on resting cortisol. Low- versus high-carbohydrate diets resulted in much higher post-exercise cortisol, after long-duration exercise (≥20 min): 0 h (0.78 [0.47, 1.1], p < 0.01), 1 h (0.81 [0.31, 1.31], p < 0.01), and 2 h (0.82 [0.33, 1.3], p < 0.01). Moderate-protein (<35%), low-carbohydrate diets had no consistent effect on resting total testosterone, however high-protein (≥35%), low-carbohydrate diets greatly decreased resting (-1.08 [-1.67, -0.48], p < 0.01) and post-exercise total testosterone (-1.01 [-2, -0.01] p = 0.05). Conclusions: Resting and post-exercise cortisol increase during the first 3 weeks of a low-carbohydrate diet. Afterwards, resting cortisol appears to return to baseline, whilst post-exercise cortisol remains elevated. High-protein diets cause a large decrease in resting total testosterone (∼5.23 nmol/L).

The interrelationship between physical activity intensity, cardiorespiratory fitness, and executive function in middle-aged adults: An observational study of office workers

Background

Previous evidence supports a beneficial effect of physical activity on executive function across the whole lifespan. Yet, the interrelationships of the intensities of physical activity, cardiorespiratory fitness, and executive function require further investigation in adults.

Aim

Using unfiltered accelerometry data and high-resolution intensity classification, we sought to estimate the associations of physical activity with cardiorespiratory fitness and executive function in adult office workers.

Methods

We included 343 full-time office workers (mean age: 42.41 years, range of age: 36-49 years). Executive function was assessed using Stroop, Trail making tests (part-B), and 2-back tests, and a composite score was produced to reflect the general executive function performance. Physical activity was assessed using the Actigraph GT3X+-monitor, worn by each participant for seven days at the hip. Raw accelerometry data were processed by the 10 Hz frequency extended method and divided into 22 intensity bins and sleep time. Cardiorespiratory fitness was estimated using the submaximal Ekblom-Bak cycle ergometer test. Data were analyzed using partial least squares regressions.

Results

In adults, cardiorespiratory fitness was closely correlated with a wide range of absolute physical activity intensity patterns. A higher level of executive function in adults was associated with both higher absolute physical activity intensities and cardiorespiratory fitness, which was independent of age, sex, and education levels. A very weak association between intensities, fitness, and executive function was observed in high-fit adults. Among low-fit adults, although a positive association started already toward the upper end of moderate intensity, there still appeared to be an association between intensities, cardiorespiratory fitness, and executive function. That is, cardiorespiratory fitness may mediate the association between absolute physical activity intensities and executive function up to a certain level.

Conclusion

The maintenance of executive function in adulthood was related to both physical activity intensities and cardiorespiratory fitness, while their interrelationship was not equal across fitness levels. It is highly recommended to consider the cardiorespiratory fitness level in future studies that focus on executive functions in aging as well when designing individualized physical activity training programs.

The Influence of Family History of Type 2 Diabetes on Metabolism during Submaximal Aerobic Exercise and in the Recovery Period in Postmenopausal Women

Aging and family history of type 2 diabetes (T2D) are known risk factors of T2D. Younger first-degree relatives (FDR) of T2D patients have shown early metabolic alterations, which could limit exercise's ability to prevent T2D. Thus, the objective was to determine whether exercise metabolism was altered during submaximal exercise in FDR postmenopausal women. Nineteen inactive postmenopausal women (control: 10, FDR: 9) aged 60 to 75 years old underwent an incremental test on a cycle ergometer with intensity ranging from 40 to 70% of peak power output. Participants consumed 50 mg of 13C-palmitate 2 h before the test. At the end of each stage, glucose, lactate, glycerol, non-esterified fatty acids and 13C-palmitate were measured in plasma, and 13CO2 was measured in breath samples. Gas exchanges and heart rate were both monitored continuously. There were no between-group differences in substrate oxidation, plasma substrate concentrations or 13C recovered in plasma or breath. Interestingly, despite exercising at a similar relative intensity to control, FDR were consistently at a lower percentage of heart rate reserve. Overall, substrate plasma concentration and oxidation are not affected by family history of T2D in postmenopausal women and therefore not a participating mechanism in the altered response to exercise previously reported. More studies are required to better understand the mechanisms involved in this response.

Efficacy of interdisciplinary rehabilitation in child cancer survivors: Impact on physical fitness, fatigue and body composition after 1-year follow-up

OBJECTIVE

Childhood cancer survivors experience reduced physical activity level, participation as well as health-related quality of life. This prospective, pre-/post-intervention and follow-up cohort study aims to determine the efficacy of an interdisciplinary rehabilitation on improving physical fitness, fatigue and body composition.

METHODS

A total of 24 childhood cancer survivors (mean age: 12.15 years ± 3.2; 14 females; 10 males) were recruited 6 months after medical treatment and received a 4-month interdisciplinary intervention. Cardiorespiratory fitness (PredVO_2peak and PredLoad_max ), body composition (dry lean weight) and quality of life (general fatigue) were assessed at baseline, post-intervention and 1-year follow-up. Linear mixed models were used to analyse data.

RESULTS

Linear mixed modelling revealed a significant main effect of time on predicted maximal load (F = 13.189, df = 36.179, p < 0.001), dry lean weight (F = 64.813, df = 37.019, p < 0.001) but also significant improvement of general fatigue score (-9.039 ± 4.300, 95% CI -17.741 to -0.336, p = 0.042), indicating a decline in general fatigue.

CONCLUSION

With emerging evidence that physical activity is safe and feasible, together with increasing numbers of childhood cancer survivors at risk for long-term chronic co-morbidities, this study advocates for better access to interdisciplinary rehabilitation programmes in order to improve their physical condition and their body composition and reduce fatigue.

The Effect of Four Weeks of Long-Term Endurance Training with and Without Propolis Supplementation on Serum Levels of Betatrophin/ANGPTL8 in Male Athletes

Background: Betatrophin/angiopoietin-like protein (ANGPTL8) is defined as an adipokine that regulates blood glucose and triglyceride levels. Objectives: This study aimed to evaluate the effect of propolis supplementation for the first time on serum levels of the hormone betatrophin, as a drug target in the treatment of dyslipidemia, in male endurance athletes for four weeks. Methods: 44 male athletes with an average age of 22 ± 3 years, a height of 177.5 ± 6.5 cm, and a weight of 76 ± 6 kg were selected in Qazvin. They were randomly divided into four groups: Supplementation, placebo, physical activity, and control. The supplementation and placebo groups received two 500 mg tablets of propolis and cellulose (in terms of shape and color, are similar to the original supplement and have no properties, flavor, and aroma) once after lunch and once after dinner, respectively. The drug treatment lasted for four weeks. The athletes' weight and serum levels of betatrophin were measured at the beginning and the end of 4 weeks of treatment. The ELISA method was used to assess the serum concentration of betatrophin. Analyzes were performed by the ANCOVA method. Results: The results showed that the long-term endurance training plus propolis supplementation would result in significant changes in the betatrophin serum levels and weight in participants (P = 0.001), but in the athletes without supplementation, these changes were not significant (P > 0.05). Conclusions: The results indicated that betatrophin serum levels in endurance athletes are increased by propolis supplementation, and their weight is decreased.

Supplementation with Vitis vinifera Jingzaojing Leaf and Shoot Extract Improves Exercise Endurance in Mice

Switching myofibers from the fast-glycolytic type to the slow-oxidative type is associated with an alleviation of the symptoms associated with various cardiometabolic diseases. This study investigates the effect of Vitis vinifera Jingzaojing leaf and shoot extract (JLSE), which is rich in phenolic compounds, on the regulation of skeletal muscle fiber-type switching, as well as the associated underlying mechanism. Male C57BL/6N mice were supplemented orally with vehicle or JLSE (300 mg/kg) and subjected to treadmill exercise training. After four weeks, mice in the JLSE-supplemented group showed significantly improved exercise endurance and mitochondrial oxidative capacity. JLSE supplementation increased the expression of sirtuin 6 and decreased Sox6 expression, thereby elevating the number of mitochondria and encouraging fast-to-slow myofiber switching. The results of our experiments suggest that JLSE supplementation reprograms myofiber composition to favor the slow oxidative type, ultimately enhancing exercise endurance.

The Role of Diets and Dietitians for Para-Athletes: A Pilot Study Based on Interviews

Efforts to provide nutrition support to para-athletes have not been established to date, and are far behind those established for athletes without disabilities. In the present study, we attempted to clarify the actual situation regarding dietary challenges of para-athletes. The aim of this study was to obtain clues to effective intervention methods that encourage the practice of sports nutrition. Six active elite para-athletes (30–70 years, four males) and a female physical therapist without physical disability participated in semi-structured interviews. All para-athletes had lower-limb disabilities and participated in the international wheelchair sports competitions (tennis, softball, and table tennis, with 2–26 years of player history). The interview items were on the ideal diet for improving competitive performance, evaluation of their typical diets, and the role of the dietitian as support. Responses obtained from participants were analyzed using quantitative content analysis by language analysis software. There are differences in the ideal diet based on the characteristics of the sport, but most participants believed that a nutritionally well-balanced diet with abundant vegetables was ideal for improving competitive performance. Para-athletes who use a wheelchair daily pay attention to their total calorie intake, because gaining weight is a critical issue for operating their wheelchairs and transferring themselves to and from their wheelchairs. Despite their world-class competition levels, none of them received routine dietary advice from dietitians. Some para-athletes did not even feel the need to engage with dietitians. Even for these para-athletes at a high level of competition, the “ideal diet” they considered was not always the optimal diet for improving their competitive performance. In addition, there are various barriers to practicing their optimal diet due to disability characteristics. Dietitians need to understand these barriers, their concerns and conflicts, and how to help them plan the optimal diet to improve their performance and maintain overall health.

Caffeine increases exercise intensity and energy expenditure but does not modify substrate oxidation during 1 h of self-paced cycling

AIM

Oral caffeine intake has been deemed as an effective supplementation strategy to enhance fat oxidation during aerobic exercise with a steady-state intensity. However, in real exercise scenarios, individuals habitually train with autoregulation of exercise intensity. This study aimed to analyze the effect of oral caffeine intake during self-paced cycling on autoregulated exercise intensity and substrate oxidation.

METHODS

Fifteen young and healthy participants (11 men and 4 women) participated in a double-blind, randomized, cross-over investigation. Each participant took part in 2 experimental days consisting of pedaling for 1 h with a self-selected wattage. Participants were told that they had to exercise at a moderate intensity to maximize fat oxidation. On one occasion participants ingested 3 mg/kg of caffeine and on the other occasion ingested a placebo. Energy expenditure, fat oxidation rate, and carbohydrate oxidation rate were continuously measured during exercise by indirect calorimetry.

RESULTS

In comparison to the placebo, caffeine intake increased the self-selected wattage (on average, 105 ± 44 vs 117 ± 45 W, respectively, P < 0.001) which represented a higher total work during the cycling session (377 ± 157 vs 422 ± 160 kJ, P < 0.001). Caffeine increased total energy expenditure (543 ± 161 vs 587 ± 155 kcal, P = 0.042) but it did not affect total fat oxidation (24.7 ± 12.2 vs 22.9 ± 11.5 g, P = 0.509) or total carbohydrate oxidation (87.4 ± 22.4 vs 97.8 ± 32.3 g, P = 0.101).

CONCLUSION

Acute caffeine ingestion before an exercise session with an individual's freedom to regulate intensity induces a higher self-selected exercise intensity and total work. The selection of a higher exercise intensity augments total energy expenditure but eliminates the effect of caffeine on substrate oxidation during exercise.

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.

A Comparison of Substrate Utilization Profiles During Maximal and Submaximal Exercise Tests in Athletes

Background

Exercise is primarily sustained by energy derived from lipids (plasma free fatty acids and intramuscular triglycerides), and glucose (plasma glucose and muscle glycogen). Substrate utilization is the pattern by which these fuel sources are used during activity. There are many factors that influence substrate utilization. We aim to delineate the effect of exercise intensity and body composition on substrate utilization.

Objective

The objective of our study was to discern the differences in substrate utilization profiles during a maximal and submaximal graded exercise test, and to determine the extent to which body composition influences substrate utilization during the exercise tests.

Methods

A total of 27 male athletes, 32.5 ± 11 years of age, were recruited for this study. Body composition was analyzed using a bioelectrical impedance analyzer. Maximal and submaximal exercise tests were performed on a treadmill. A novel graded submaximal treadmill protocol was used for the submaximal test.

Results

Average percent body fat (PBF) was 15.8 ± 5%. Average maximal oxygen consumption (VO₂max) was 47.6 ± 9 mL/kg/min, while the average exercise intensity (percent VO₂max) at which participants were shifting to glucose predominance for energy during the maximal and submaximal tests were 76 ± 8.3% and 58.4 ± 21.1%, respectively. A paired-samples t-test was conducted to compare percent VO₂max at crossover point in maximal and submaximal graded exercise tests. There was a significant difference in percent VO₂max at the crossover point for maximal (76 ± 8.3%) and submaximal (58 ± 21.1%) tests (t = 4.752, p = 0.001). A linear regression was performed to elucidate the interaction between exercise intensity at the crossover point and body composition during a maximal and submaximal graded exercise test. There was a significant effect of PBF on percent VO₂max at crossover point during the maximal graded exercise test [F(1,24) = 9.10, P = 0.006] with an R² of 0.245. However, there was no significant effect of PBF on percent VO₂max at crossover point during the submaximal graded exercise test (P > 0.05).

Conclusion

Substrate utilization, represented by the crossover point, is dependent on the rate of increase in exercise intensity. At maximal efforts, the crossover to carbohydrates from fats as the predominant fuel source occurs at a significantly later stage of percent VO₂max than at submaximal efforts. Furthermore, body composition represented by PBF is a significant predictor of substrate utilization during maximal efforts. Athletes with a relatively higher PBF are more likely to have increased lipid oxidation during high intensity exercises than those with a lower body fat percentage.

Biomarkers and genetic polymorphisms associated with maximal fat oxidation during physical exercise: implications for metabolic health and sports performance

The maximal fat oxidation rate (MFO) assessed during a graded exercise test is a remarkable physiological indicator associated with metabolic flexibility, body weight loss and endurance performance. The present review considers existing biomarkers related to MFO, highlighting the validity of maximal oxygen uptake and free fatty acid availability for predicting MFO in athletes and healthy individuals. Moreover, we emphasize the role of different key enzymes and structural proteins that regulate adipose tissue lipolysis (i.e., triacylglycerol lipase, hormone sensitive lipase, perilipin 1), fatty acid trafficking (i.e., fatty acid translocase cluster of differentiation 36) and skeletal muscle oxidative capacity (i.e., citrate synthase and mitochondrial respiratory chain complexes II-V) on MFO variation. Likewise, we discuss the association of MFO with different polymorphism on the ACE, ADRB3, AR and CD36 genes, identifying prospective studies that will help to elucidate the mechanisms behind such associations. In addition, we highlight existing evidence that contradict the paradigm of a higher MFO in women due to ovarian hormones activity and highlight current gaps regarding endocrine function and MFO relationship.

Oligofructose-Enriched Inulin Intake, Gut Microbiome Characteristics, and the V̇O2 Peak Response to High-Intensity Interval Training in Healthy Inactive Adults

BACKGROUND

The gut microbiome has been associated with cardiorespiratory fitness.

OBJECTIVES

To assess the effects of oligofructose (FOS)-enriched inulin supplementation on the gut microbiome and the peak oxygen uptake (V̇O2peak) response to high-intensity interval training (HIIT).

METHODS

The study was a randomized controlled trial. Forty sedentary and apparently healthy adults [n = 31 women; aged 31.8 ± 9.8 y, BMI (in kg⋅m-2) 25.9 ± 4.3] were randomly allocated to 1) 6 wk of supervised HIIT (4 × 4-min bouts at 85-95% peak heart rate, interspersed with 3 min of active recovery, 3·wk-1) + 12 g·d-1 of FOS-enriched inulin (HIIT-I) or 2) 6 wk of supervised HIIT (3·wk-1, 4 × 4-min bouts) + 12 g·d-1 of maltodextrin/placebo (HIIT-P). Each participant completed an incremental treadmill test to assess V̇O2peak and ventilatory thresholds (VTs), provided a stool and blood sample, and completed a 24-h diet recall questionnaire and FFQ before and after the intervention. Gut microbiome analyses were performed using metagenomic sequencing. Fecal short-chain fatty acids were measured by mass spectrometry.

RESULTS

There were no differences in the mean change in V̇O2peak response between groups (P = 0.58). HIIT-I had a greater improvement in VTs than HIIT-P [VT1 (lactate accumulation): mean difference + 4.3% and VT2 (lactate threshold): +4.2%, P < 0.05]. HIIT-I had a greater increase in the abundance of Bifidobacterium taxa [false discovery rate (FDR) < 0.05] and several metabolic processes related to exercise capacity (FDR < 0.05). Exploratory analysis of merged data found participants with a greater response to HIIT (V̇O2peak ≥3.5 mL⋅kg-1⋅min-1) had a 2.2-fold greater mean abundance of gellan degradation pathways (FDR < 0.05) and a greater, but not significant, abundance of Bifidobacterium uniformis species (P < 0.00023, FDR = 0.08).

CONCLUSIONS

FOS-enriched inulin supplementation did not potentiate HIIT-induced improvements in V̇O2peak but led to gut microbiome changes possibly associated with greater ventilatory threshold improvements in healthy inactive adults. Gellan degradation pathways and B. uniformis spp. were associated with greater V̇O2peak responses to HIIT.

High-intensity interval training improves fat oxidation during submaximal exercise in active young men

This study aimed to examine the effects of four-weeks high-intensity interval training (HIIT) on fat oxidation responses during submaximal exercise in active young men. For this purpose, 20 active young men (who participated in the exercise three times per week) were divided into two groups, including a training group (age: 19.3±0.48 years, V̇O2peak 2.9±0.35 l/min, n=10) and a control group (age: 19.7±0.67 years, V̇O2peak 2.7±0.26 l/min, n=10). The training group performed high-intensity interval training for three sessions per week. Specifically, each session included 8-11 intensive cycling efforts comprising of 60 s duration. A 75 s low pedalling rate (30 W) was used as an active recovery between the intervals. Furthermore, a V̇O2peak test was performed prior to, at the end of two weeks and after the training period. Also, a 60 min constant cycling protocol was performed at ~60% V̇O2peak, in addition to the V̇O2peak test, before and after the training protocol. To assess plasma free fatty acids and glucose, blood samples were taken during a 60-min aerobic exercise prior to and following the training period. An increase (17.8%) in V̇O2peak was observed for the HIIT group after the training period compared to the control group (P<0.05). The HIIT group performed the 60 min sub-maximal exercise test at a lower percentage of V̇O2peak, and decreases in the respiratory exchange ratio were greater in the HIIT group than in the control group (P<0.05). Compared to the pre-test values and control group results, the HIIT group used less carbohydrate and more lipid oxidation during submaximal exercise (P<0.05). The present study’s results indicate that short-term low volume HIIT can increase aerobic capacity and fat oxidation during submaximal exercise.

Intermittent fasting & performance: The iFast clinical trial protocol

There is increasing evidence from animal and human studies suggesting that fasting can play a role in disease prevention, weight control and longevity. However, few studies have compared exercise performances in individuals adhering to an intermittent fasting (IF) in comparison to individuals who are not. Given the rising popularity of IF we aim to investigate whether this type eating pattern will improve cardiovascular performance over a period of 12 weeks through VO₂ max measurements in participants from a Lebanese community. Additionally, we will study the variation of different health parameters, physical performance and biomarkers potentially affected by IF. Participants will be recruited from a large university community and randomized into 4 arms. Baseline information will be collected from all participants, which includes biological, physical, nutritional, medical and psychological data. Two arms will follow a time-restricted fasting diet with and without physical exercise, one arm will exercise without fasting, and one will act as a control group. Throughout the study, measurements will be repeated, and data analysis will follow to evaluate results.

Diurnal variation of fat oxidation rate and energy expenditure in an acute bout of endurance exercise by young healthy males

Background:

Few studies have reported that circadian rhythm affects fat oxidation (FOx) during exercise. Time-of-day causing greater FOx and energy expenditure (EE) during exercise would be beneficial in the prevention of physical inactivity-related health disorders such as metabolic syndrome. The study aims to compare EE and FOx rate after an endurance exercise session done in the morning and late-afternoon hours by apparently healthy young male participants.

Material and Methods:

The present crossover quasi-experimental study involved 10 moderately active but physically untrained male participants of age 18–25 years with normal body mass index. Participants did a steady-state exercise on a motorized treadmill for 30 minutes at a moderate-intensity (50 ± 2% of their heart rate reserve) on two separate occasions at 9:00–10:00 and 15:00–16:00. A similar meal followed by 2 hours of fasting was done before each trial session. During the last 2 minutes of the exercise session, the respiratory gas analysis estimated volume of oxygen (VO₂) and volume of carbon dioxide (VCO₂) consumed in L/min. Indirect calorimetry equations assessed FOx (mg/min), EE (Kcal/min) and respiratory exchange ratio (RER). Data of one participant were removed to adjust for extreme chronotype. Paired t-test was applied, and P ≤ 0.05 was considered significant.

Results:

Morning versus late-afternoon variations in FOx (269 ± 110 vs 290 ± 110, P = 0.016), RER (0.86 ± 0.05 vs 0.85 ± 0.05, P = 0.040), EE (5.454 ± 0.987 vs 5.494 ± 0.959, P = 0.079) and VO2 (1.104 ± 0.201 vs 1.113 ± 0.196, P = 0.035) were present after adjustment for chronotype.

Conclusion:

In an acute bout of endurance, exercise done by young and healthy male individuals, FOx was significantly higher, while EE tends to be higher in late-afternoon than in the morning.

Traffic-related air pollution and endurance exercise: Characterizing non-targeted serum metabolomics profiling

Although the exposure to traffic-related air pollution (TRAP) has emerged as one of main problem worldwide to inhabitants' health in urban centers, its impact on metabolic responses during exercise is poorly understood. The aim of study was to characterize the profile of non-target serum metabolomics during prolonged exercise performed under TRAP conditions. Ten healthy men completed two 90 min constant-load cycling trials under conditions of either TRAP or filtered air. Experimental trials were performed in a chamber located on an avenue with a high volume of vehicle traffic. Blood samples were taken at 30 min, 60 min, and 90 min of exercise. Based on Nuclear Magnetic Resonance metabolomics, the non-target analysis was used to assess the metabolic profile. Twelve, 16 and 18 metabolites were identified as discriminants. These were: at 30 min of exercise, the coefficient of determination (R²) 0.98, the predictive relevance, (Q²) 0.12, and the area under the curve (AUC) 0.91. After 60 min of exercise: (R²: 0.99, Q²: 0.09, AUC: 0.94); and at 90 min of exercise (R²: 0.91, Q²: <0.01, AUC: 0.89), respectively. The discriminant metabolites were then considered for the target analysis, which demonstrated that the metabolic pathways of glycine and serine metabolism (p = 0.03) had been altered under TRAP conditions at 30 min of exercise; arginine and proline metabolism (p = 0.04) at 60 min of exercise; and glycolysis (p = 0.05) at 90 min of exercise. The present results suggest that exposure to TRAP during prolonged exercise leads to a significant change in metabolomics, characterized by a transitional pattern and lastly, impairs the glucose metabolism.

Comparison of the Ramp and Step Incremental Exercise Test Protocols in Assessing the Maximal Fat Oxidation Rate in Youth Cyclists

The incremental exercise test is the most common method in assessing the maximal fat oxidation (MFO) rate. The main aim of the study was to determine whether the progressive linear RAMP test can be used to assess the maximal fat oxidation rate along with the intensities that trigger its maximal (FAT_max) and its minimal (FAT_min) values. Our study comprised 57 young road cyclists who were tested in random order. Each of them was submitted to two incremental exercise tests on an electro-magnetically braked cycle-ergometer - STEP (50 W·3 min^-1) and RAMP (~0.278 W·s^-1) at a 7-day interval. A stoichiometric equation was used to calculate the fat oxidation rate, while the metabolic thresholds were defined by analyzing ventilation gases. The Student’s T-test, Bland-Altman plots and Pearson’s linear correlations were resorted to in the process of statistical analysis. No statistically significant MFO variances occurred between the tests (p = 0.12) and its rate amounted to 0.57 ± 0.15 g·min^-1 and 0.53 ± 0.17 g·min^-1 in the STEP and RAMP, respectively. No statistically significant variances in the absolute and relative (to maximal) values of oxygen uptake and heart rate were discerned at the FAT_max and FAT_min intensities. The RAMP test displayed very strong oxygen uptake correlations between the aerobic threshold and FAT_max (r = 0.93, R² = 0.87, p < 0.001) as well as the anaerobic threshold and FAT_min (r = 0.88, R² = 0.78, p < 0.001). Our results corroborate our hypothesis that the incremental RAMP test as well as the STEP test are reliable tools in assessing MFO, FAT_max and FAT_min intensities.

Divergent serum metabolomic, skeletal muscle signaling, transcriptomic, and performance adaptations to fasted versus whey protein-fed sprint interval training

Sprint interval training (SIT) is a time-efficient alternative to endurance exercise, conferring beneficial skeletal muscle metabolic adaptations. Current literature has investigated the nutritional regulation of acute and chronic exercise-induced metabolic adaptations in muscle following endurance exercise, principally comparing the impact of training in fasted and carbohydrate-fed (CHO) conditions. Alternative strategies such as exercising in low CHO, protein-fed conditions remain poorly characterized, specifically pertaining to adaptations associated with SIT. Thus, this study aimed to compare the metabolic and performance adaptations to acute and short-term SIT in the fasted state with preexercise hydrolyzed (WPH) or concentrated (WPC) whey protein supplementation. In healthy males, preexercise protein ingestion did not alter exercise-induced increases in PGC-1α, PDK4, SIRT1, and PPAR-δ mRNA expression following acute SIT. However, supplementation of WPH beneficially altered acute exercise-induced CD36 mRNA expression. Preexercise protein ingestion attenuated acute exercise-induced increases in muscle pan-acetylation and PARP1 protein content compared with fasted SIT. Acute serum metabolomic differences confirmed greater preexercise amino acid delivery in protein-fed compared with fasted conditions. Following 3 wk of SIT, training-induced increases in mitochondrial enzymatic activity and exercise performance were similar across nutritional groups. Interestingly, resting muscle acetylation status was downregulated in WPH conditions following training. Such findings suggest preexercise WPC and WPH ingestion positively influences metabolic adaptations to SIT compared with fasted training, resulting in either similar or enhanced performance adaptations. Future studies investigating nutritional modulation of metabolic adaptations to exercise are warranted to build upon these novel findings.NEW & NOTEWORTHY These are the first data to show the influence of preexercise protein on serum and skeletal muscle metabolic adaptations to acute and short-term sprint interval training (SIT). Preexercise whey protein concentrate (WPC) or hydrolysate (WPH) feeding acutely affected the serum metabolome, which differentially influenced acute and chronic changes in mitochondrial gene expression, intracellular signaling (acetylation and PARylation) resulting in either similar or enhanced performance outcomes when compared with fasted training.

Fueling Gut Microbes: A Review of the Interaction between Diet, Exercise, and the Gut Microbiota in Athletes

The athlete's goal is to optimize their performance. Towards this end, nutrition has been used to improve the health of athletes' brains, bones, muscles, and cardiovascular system. However, recent research suggests that the gut and its resident microbiota may also play a role in athlete health and performance. Therefore, athletes should consider dietary strategies in the context of their potential effects on the gut microbiota, including the impact of sports-centric dietary strategies (e.g., protein supplements, carbohydrate loading) on the gut microbiota as well as the effects of gut-centric dietary strategies (e.g., probiotics, prebiotics) on performance. This review provides an overview of the interaction between diet, exercise, and the gut microbiota, focusing on dietary strategies that may impact both the gut microbiota and athletic performance. Current evidence suggests that the gut microbiota could, in theory, contribute to the effects of dietary intake on athletic performance by influencing microbial metabolite production, gastrointestinal physiology, and immune modulation. Common dietary strategies such as high protein and simple carbohydrate intake, low fiber intake, and food avoidance may adversely impact the gut microbiota and, in turn, performance. Conversely, intake of adequate dietary fiber, a variety of protein sources, and emphasis on unsaturated fats, especially omega-3 (ɷ-3) fatty acids, in addition to consumption of prebiotics, probiotics, and synbiotics, have shown promising results in optimizing athlete health and performance. Ultimately, while this is an emerging and promising area of research, more studies are needed that incorporate, control, and manipulate all 3 of these elements (i.e., diet, exercise, and gut microbiome) to provide recommendations for athletes on how to "fuel their microbes."

Serum Branched-Chain Amino Acid Metabolites Increase in Males When Aerobic Exercise Is Initiated with Low Muscle Glycogen

This study used global metabolomics to identify metabolic factors that might contribute to muscle anabolic resistance, which develops when aerobic exercise is initiated with low muscle glycogen using global metabolomics. Eleven men completed this randomized, crossover study, completing two cycle ergometry glycogen depletion trials, followed by 24 h of isocaloric refeeding to elicit low (LOW; 1.5 g/kg carbohydrate, 3.0 g/kg fat) or adequate (AD; 6.0 g/kg carbohydrate 1.0 g/kg fat) glycogen. Participants then performed 80 min of cycling (64 ± 3% VO₂ peak) while ingesting 146 g carbohydrate. Serum was collected before glycogen depletion under resting and fasted conditions (BASELINE), and before (PRE) and after (POST) exercise. Changes in metabolite profiles were calculated by subtracting BASELINE from PRE and POST within LOW and AD. There were greater increases (p < 0.05, Q < 0.10) in 64% of branched-chain amino acids (BCAA) metabolites and 69% of acyl-carnitine metabolites in LOW compared to AD. Urea and 3-methylhistidine had greater increases (p < 0.05, Q < 0.10) in LOW compared to AD. Changes in metabolomics profiles indicate a greater reliance on BCAA catabolism for substrate oxidation when exercise is initiated with low glycogen stores. These findings provide a mechanistic explanation for anabolic resistance associated with low muscle glycogen, and suggest that exogenous BCAA requirements to optimize muscle recovery are likely greater than current recommendations.

The Metabolic Signature of Cardiorespiratory Fitness: A Systematic Review

Background

Cardiorespiratory fitness (CRF) is a potent health marker, the improvement of which is associated with a reduced incidence of non-communicable diseases and all-cause mortality. Identifying metabolic signatures associated with CRF could reveal how CRF fosters human health and lead to the development of novel health-monitoring strategies.

Objective

This article systematically reviewed reported associations between CRF and metabolites measured in human tissues and body fluids.

Methods

PubMed, EMBASE, and Web of Science were searched from database inception to 3 June, 2021. Metabolomics studies reporting metabolites associated with CRF, measured by means of cardiopulmonary exercise test, were deemed eligible. Backward and forward citation tracking on eligible records were used to complement the results of database searching. Risk of bias at the study level was assessed using QUADOMICS.

Results

Twenty-two studies were included and 667 metabolites, measured in plasma (n = 619), serum (n = 18), skeletal muscle (n = 16), urine (n = 11), or sweat (n = 3), were identified. Lipids were the metabolites most commonly positively (n = 174) and negatively (n = 274) associated with CRF. Specific circulating glycerophospholipids (n = 85) and cholesterol esters (n = 17) were positively associated with CRF, while circulating glycerolipids (n = 152), glycerophospholipids (n = 42), acylcarnitines (n = 14), and ceramides (n = 12) were negatively associated with CRF. Interestingly, muscle acylcarnitines were positively correlated with CRF (n = 15).

Conclusions

Cardiorespiratory fitness was associated with circulating and muscle lipidome composition. Causality of the revealed associations at the molecular species level remains to be investigated further. Finally, included studies were heterogeneous in terms of participants’ characteristics and analytical and statistical approaches.

PROSPERO Registration Number

CRD42020214375.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01590-y.

Three-Day Dietary Manipulation in Multiple Sclerosis: Exercise and Fatigue Outcomes

Background

In persons with multiple sclerosis (MS), the effect of nutrition on exercise performance and fatigue remains unknown. The objective was to determine whether a 3-day diet high in triglycerides (FAT) compared with a 3-day diet high in carbohydrates (CARB) would improve fatigue and exercise performance in persons with MS.

Methods

A randomized controlled crossover design was incorporated to study FAT versus CARB on submaximal cycling endurance (60% of peak oxygen consumption), substrate utilization, and fatigue in 12 persons with mild-to-moderate MS (Expanded Disability Status Scale score, 2.0-5.0) and 12 age- and sex-matched controls.

Results

There were no differences in cycling time between diets in either group (P = .29). The MS group had no changes in fatigue between diets (P = .64); the control group demonstrated increased total mental fatigue after FAT (P = .05). The control group increased carbohydrate oxidation by 24% at rest and 13% during exercise after CARB. Similarly, the control group significantly increased fat oxidation after FAT by 22% at rest and 68% during exercise (P = .01). These changes were not seen in the MS group. Compared with controls, persons with MS oxidized approximately 50% less fat during exercise after FAT (P = .05).

Conclusions

Neither CARB nor FAT altered submaximal exercise performance or baseline fatigue in the MS group. The results suggest that persons with MS are unable to adapt to dietary changes and oxidize fatty acids as efficiently as controls.

18β-glycyrrhetinic acid improves high-intensity exercise performance by promoting glucose-dependent energy production and inhibiting oxidative stress in mice

It has been shown that 18β-glycyrrhetinic acid (18β-GA), the main bioactive compound of licorice, can modulate oxidative stress and metabolic processes in liver and skin. Given the critical role of oxidative stress and energy metabolism in exercise-induced fatigue, we hypothesized that 18β-GA could exert an ergogenic action by inhibiting excess reactive oxygen species (ROS) induction and promoting energy production in muscles. Mice were gavage-fed with 18β-GA for four consecutive days. Running ability was assessed based on the exhaustive treadmill test with high- and moderate-intensity. Western blot analysis, enzyme-linked immunosorbent assay, and immunofluorescence staining were used to measure the changes of muscle fatigue-related markers, oxidative stress status, and energy metabolism in response to 18β-GA exposure. Treatment with 18β-GA significantly increased the exhaustive running distance (~37%) in the high-intensity exercise, but not in the moderate-intensity exercise. Mechanistically, reduction of oxidative stress and induction of antioxidants (SOD, CAT, and GSH) by 18β-GA were observed. Moreover, 18β-GA treatment caused an improved preservation of muscle glycogen (12%), which was associated with upregulation of glucose transporter 4 (GLUT4) (91%) and increased insulin level (17%). The findings of the present study clearly suggest that 18β-GA holds excellent potential as a novel bioactive agent against high-intensity exercise-induced fatigue.

The Influence of Endurance Training on the Lipid Profile, Body Mass Composition and Cardiovascular Efficiency in Middle-Aged Cross-Country Skiers

Monitoring the training of amateur long-distance cross-country skiers (XCS) can help athletes’ achieve a higher exercise capacity and protect their health. The aim of this study was to assess body composition changes and lipid profiles in middle-aged amateur long-distance XCS after four months of training, including specialized roller ski training. The results of the time-to-exhaustion (TTE) test and blood tests and changes in body composition were analyzed with basic descriptive statistics: the paired Wilcoxon test was used to compare the results (initial and final). Spearman’s rank correlation coefficient (R) was used to assess the influence of various variables on maximum oxygen uptake (VO₂max). The findings show that training of amateur long-distance XCS improved maximal oxygen uptake (p = 0.008) and had a positive effect on fat reduction, measured in percentages (p = 0.038) and in kilograms (p = 0.023), but did not change blood lipids or other parameters. Further research could focus on other aspects of the annual training cycle: the competition period, and women in a larger group of athletes. Training with roller skis and a cross-country skiing training machine (a specialized machine for strengthening the arms and upper body) can support health and prevent obesity, overweight, and cardiovascular disease.

Inclusion of sprints during moderate-intensity continuous exercise enhances post-exercise fat oxidation in young males

To assess the physiological demand of including high-intensity efforts during continuous exercise, we designed a randomized crossover study, where 12 physically active young males executed three different exercises in random order: FATmax - continuous exercise at the highest fat oxidation zone (FATmax); 2min-130% - FATmax interspersed by a 2-min bout at 130% of the maximal oxygen uptake associated intensity (iV̇O2max); and 20s:10s-170% - FATmax interspersed by four 20-s bouts at 170%iV̇O2max interpolated by 10s of passive recovery. We measured oxygen uptake (V̇O2), blood lactate concentration ([LAC]), respiratory exchange rate (RER), fat and carbohydrate (CHO) oxidation. For statistical analyses, repeated measures ANOVA was applied. Although no differences were found for average V̇O2 or carbohydrate oxidation rate, the post-exercise fat oxidation rate was 37.5% and 50% higher during 2min-130% and 20s:10s-170%, respectively, compared to FATmax, which also presented lower values of RER during exercise compared to 2min-130% and 20s:10s-170% (p<0.001 in both), and higher values post-exercise (p=0.04 and p=0.002, respectively). The [LAC] was higher during exercise when high-intensity bouts were applied (p<0.001 for both) and higher post-exercise on the intermittent one compared to FATmax (p=0.016). The inclusion of high-intensity efforts during moderate-intensity continuous exercise promoted higher physiological demand and post-exercise fat oxidation. Novelty bullets • The inclusion of 2-min efforts modifies continuous exercise demands • Maximal efforts can increase post-exercise fat oxidation • 2-min maximal efforts, continuous or intermittent, presents similar demands.

Priming metabolism with the type 5 phosphodiesterase: the role of cGMP-hydrolyzing enzymes

The cyclic guanosine monophosphate (cGMP) signaling system is one of the most prominent regulators of many physiopathological processes in humans and rodents. It has been strongly established as an accomplished cellular signal involved in the regulation of energy homeostasis and cell metabolism, and pharmacological enhancement of cGMP has shown beneficial effects in metabolic disorders models. cGMP intracellular levels are finely regulated by phosphodiesterases (PDEs). The main enzyme responsible for the degradation of cGMP is PDE5. Preclinical and clinical studies have shown that PDE5 inhibitors (PDE5i) have beneficial effects on improving insulin resistance and glucose metabolism representing a promising therapeutic strategy for the treatment of metabolic disorders. This review aims to describe the molecular basis underlying the use of PDE5i to prompt cell metabolism and summarize current clinical trials assessing the effects of PDE5i on glucose metabolism.

Adaptation of fuel selection to acute decrease in voluntary energy expenditure is governed by dietary macronutrient composition in mice

In humans, exercise-induced thermogenesis is a markedly variable component of total energy expenditure, which had been acutely affected worldwide by COVID-19 pandemic-related lockdowns. We hypothesized that dietary macronutrient composition may affect metabolic adaptation/fuel selection in response to an acute decrease in voluntary activity. Using mice fed short-term high-fat diet (HFD) compared to low-fat diet (LFD)-fed mice, we evaluated whole-body fuel utilization by metabolic cages before and 3 days after omitting a voluntary running wheel in the cage. Short-term (24-48 h) HFD was sufficient to increase energy intake, fat oxidation, and decrease carbohydrate oxidation. Running wheel omission did not change energy intake, but resulted in a significant 50% decrease in total activity and a ~20% in energy expenditure in the active phase (night-time), compared to the period with wheel, irrespective of the dietary composition, resulting in significant weight gain. Yet, while in LFD wheel omission significantly decreased active phase fat oxidation, thereby trending to increase respiratory exchange ratio (RER), in HFD it diminished active phase carbohydrate oxidation. In conclusion, acute decrease in voluntary activity resulted in positive energy balance in mice on both diets, and decreased oxidation of the minor energy (macronutrient) fuel source, demonstrating that dietary macronutrient composition determines fuel utilization choices under conditions of acute changes in energetic demand.

The Effects of Exercise on β-Hydroxybutyrate Concentrations over a 36-h Fast: A Randomized Crossover Study

PURPOSE

This study assessed β-hydroxybutyrate (BHB) concentration during a short-term fast and the degree to which an initial bout of exercise influences the rate of ketogenesis.

METHODS

Twenty subjects (11 male, 9 female) completed two 36-h fasts, with one protocol requiring the subject to complete a treadmill exercise session at the beginning of the fast. BHB levels were assessed via portable meter every 2 h, along with mood and hunger ratings. Venipuncture was performed every 12 h.

RESULTS

The mean (SD) areas under the curve for BHB concentration were 19.19 (2.59) mmol·L-1 (nonexercised) and 27.49 (2.59) mmol·L-1 (exercised), yielding a difference of 8.30 mmol·L-1 between conditions (95% posterior probability interval (PPI), 1.94 to 14.82 mmol·L-1; posterior probability (PP) = 0.99). The mean (SD) times to BHB concentration of 0.5 mmol·L-1 were 21.07 (2.95) h (nonexercised) and 17.5 (1.69) h (exercised), a 3.57-h difference (95% PPI, -2.11 to 10.87 h; PP = 0.89). The differences in area under the curve between conditions were 5.07 μU·mL-1 (95% PPI, -21.64 to 36.18 μU·mL-1; PP = 0.67) for insulin, 97.13 pg·mL-1 (95% PPI, 34.08 to 354.21 pg·mL-1; PP = 0.98) for glucagon, and 20.83 (95% PPI, 4.70 to 24.22; PP = 0.99) for the insulin/glucagon ratio.

CONCLUSIONS

Completing aerobic exercise at the beginning of a fast accelerates the production of BHB throughout the fast without altering subjective feelings of hunger, thirst, stomach discomfort, or mood. Insulin and the insulin/glucagon ratio experience a marked reduction within the first 12 h of fasting and was not altered with exercise. Thus, exercising at the beginning of a fast may improve the metabolic outcomes of fasting.

Impact of moderate exercise on fatty acid oxidation in pancreatic β-cells and skeletal muscle

Fatty acids (FA) play a crucial role in glycaemia regulation in healthy and metabolic disorders conditions through various mechanisms. FA oxidation is one of the processes involved in lipid metabolism and can be modulated by exercise. Nowadays, physical activity is known to be an effective strategy for the prevention and treatment of Type 2 Diabetes. Moreover, its intensity, its duration, the sex-gender, the prandial state, exerkines… are as many parameters that can influence glycaemic control. However, the widely debated question is to determine the best type of exercise for patients with metabolic disorders. In this review, we will discuss the impact of exercise intensity, especially moderate activity, on glycaemic control by focussing on FA oxidation in pancreatic β-cells and skeletal muscle. Finally, thanks to all the recent data, we will determine whether moderate physical activity is a good therapeutic strategy and if FA oxidation represents a target of interest to treat diabetic, obese and insulin-resistant patients.

Weight Loss Strategies in Male Competitors of Combat Sport Disciplines

Background and objective: The use of suboptimal weight loss strategies in order to reach specific weight ranges as observed in combat sport disciplines can give rise to severe health problems. However, particular aspects regarding management of weight category comparing three sport disciplines remain to be investigated. Therefore, the aim of the present study was to obtain information regarding the weight loss strategies that competitors performed before a tournament. Materials and Methods: This article describes the most common dietary-nutritional strategies used by 140 national university male competitors of judo (n = 52), karate (n = 40) and taekwondo (n = 48) in order to achieve a specific weight, according to the rapid weight loss questionnaire (RWLQ) and the EAT-27 questionnaire. Results: Around 50% of participants were not involved in a weight loss process. Among the remaining participants, we considered three periods for weight reduction: less than 1 week (35% in judo, 8% in karate and 19% in taekwondo), less than 1 month (17% in judo, 15% in karate and 26% in taekwondo) and more than 1 month (0% in judo, 5% in karate and 21% in taekwondo). Severe fasting, focused on food/water restriction, was the most commonly used strategy, being more frequent in judo players. Light weight judo practitioners generally lost 2–5 kg before the contest. One third of participants avoided carbohydrate consumption when performing food restriction. Finally, individuals that reduced weight in the last week seemed to develop an unhealthy psychological relationship with food. Conclusion: All these aspects could be particularly relevant, providing information regarding how competitors manage basic nutritional concepts that guide dieting strategies. This information is relevant to prepare future educational interventions in the area of nutrition for competitors, coaches and technical staff.

Exercise, Nutrition, and Supplements in the Muscle Carnitine Palmitoyl-Transferase II Deficiency: New Theoretical Bases for Potential Applications

Carnitine palmitoyltransferase II (CPTII) deficiency is the most frequent inherited disorder regarding muscle fatty acid metabolism, resulting in a reduced mitochondrial long-chain fatty acid oxidation during endurance exercise. This condition leads to a clinical syndrome characterized by muscle fatigue and/or muscle pain with a variable annual frequency of severe rhabdomyolytic episodes. While since the CPTII deficiency discovery remarkable scientific advancements have been reached in genetic analysis, pathophysiology and diagnoses, the same cannot be said for the methods of treatments. The current recommendations remain those of following a carbohydrates-rich diet with a limited fats intake and reducing, even excluding, physical activity, without, however, taking into account the long-term consequences of this approach. Suggestions to use carnitine and medium chain triglycerides remain controversial; conversely, other potential dietary supplements able to sustain muscle metabolism and recovery from exercise have never been taken into consideration. The aim of this review is to clarify biochemical mechanisms related to nutrition and physiological aspects of muscle metabolism related to exercise in order to propose new theoretical bases of treatment which, if properly tested and validated by future trials, could be applied to improve the quality of life of these patients.

Accelerometer-measured physical activity and sedentary time are associated with maximal fat oxidation in young adults

The present work aimed to examine the association between physical activity (PA) and sedentary behaviour with maximal fat oxidation (MFO) in young individuals. A total of 77 active adults (30 women; 22.8 ± 4.5 years) were included in this cross-sectional study in which PA and sedentary behaviour were measured using accelerometers for 7 consecutive days. PA was classified into different intensities (i.e. light, moderate, vigorous, and moderate-to-vigorous) and sedentary behaviour into sedentary time (i.e. time, number of bouts, and length of bouts) and sedentary breaks (i.e. time, number of breaks, and length of breaks). MFO was determined using a graded cycloergometer test through indirect calorimetry and relativized to lean mass (MFO_LM) and lean leg mass (MFO_LL). Positive associations were found for light and vigorous PA in relation with MFO, MFO_LM and MFO_LL, independently of cofounders (P ≤ 0.01). Moreover, a negative association was found between MFO and MFO_LM and the length of sedentary bouts which was accentuated after adjusting by cardiorespiratory fitness (P ≤ 0.05). These results suggest that light and vigorous PA and sedentary behaviour are related to MFO during exercise. Despite this, further interventional studies are needed to clarify if increments of light and vigorous PA could enhance MFO in different populations.

Supplement Intake in Recreational Vegan, Vegetarian, and Omnivorous Endurance Runners-Results from the NURMI Study (Step 2)

Nutrient deficiency is a common cause of underperformance in endurance athletes, and supplement intake is frequently considered compensatory for vegan and vegetarian athletes specifically. This study aimed to investigate the patterns of supplement intake among vegan, vegetarian, and omnivorous distance (>10 km) runners and its association with age, sex, and race distance. From a total of 317 runners who participated in an online survey, 220 distance runners (mean age: 38.5 years; mean BMI: 21.75 kg/m²) were selected for the final sample after data clearance and assigned to 100 omnivores, 40 vegetarians, or 80 vegans. Sociodemographic information, racing experience, and patterns of supplement intake, including type, frequency, dosage, etc., were collected using a questionnaire. Macronutrient intake was assessed using a food frequency questionnaire. ANOVA and logistic regression were used for data analysis. The prevalence of supplement intake was 51% for total runners and 72% among vegan runners. Age, sex, and race distance had no significant effect on the type of supplement intake (p > 0.05). Compared to omnivores and vegetarians, vegan runners reported consuming more vitamin (but not carbohydrate/protein or mineral) supplements (p < 0.05). Vitamin B₁₂, magnesium, and multivitamin had the most prevalent use amongst micronutrient supplements. This study points to a central role for supplementary nutritional strategies in different groups of distance runners. The present findings may help future investigations by design to identify specific requirements of endurance runners when adhering to specific kinds of diet particularly plant-based diets.

Timing of chocolate intake affects hunger, substrate oxidation, and microbiota: A randomized controlled trial

Eating chocolate in the morning or in the evening/at night, may differentially affect energy balance and impact body weight due to changes in energy intake, substrate oxidation, microbiota (composition/function), and circadian-related variables. In a randomized controlled trial, postmenopausal females (n = 19) had 100 g of chocolate in the morning (MC), in the evening/at night (EC), or no chocolate (N) for 2 weeks and ate any other food ad libitum. Our results show that 14 days of chocolate intake did not increase body weight. Chocolate consumption decreased hunger and desire for sweets (P < .005), and reduced ad libitum energy intake by ~300 kcal/day during MC and ~150 kcal/day during EC (P = .01), but did not fully compensate for the extra energy contribution of chocolate (542 kcal/day). EC increased physical activity by +6.9%, heat dissipation after meals +1.3%, and carbohydrate oxidation by +35.3% (P < .05). MC reduced fasting glucose (4.4%) and waist circumference (-1.7%) and increased lipid oxidation (+25.6%). Principal component analyses showed that both timings of chocolate intake resulted in differential microbiota profiles and function (P < .05). Heat map of wrist temperature and sleep records showed that EC induced more regular timing of sleep episodes with lower variability of sleep onset among days than MC (60 min vs 78 min; P = .028). In conclusion, having chocolate in the morning or in the evening/night results in differential effects on hunger and appetite, substrate oxidation, fasting glucose, microbiota (composition and function), and sleep and temperature rhythms. Results highlight that the "when" we eat is a relevant factor to consider in energy balance and metabolism.

Initiating aerobic exercise with low glycogen content reduces markers of myogenesis but not mTORC1 signaling

Background

The effects of low muscle glycogen on molecular markers of protein synthesis and myogenesis before and during aerobic exercise with carbohydrate ingestion is unclear. The purpose of this study was to determine the effects of initiating aerobic exercise with low muscle glycogen on mTORC1 signaling and markers of myogenesis.

Methods

Eleven men completed two cycle ergometry glycogen depletion trials separated by 7-d, followed by randomized isocaloric refeeding for 24-h to elicit low (LOW; 1.5 g/kg carbohydrate, 3.0 g/kg fat) or adequate (AD; 6.0 g/kg carbohydrate, 1.0 g/kg fat) glycogen. Participants then performed 80-min of cycle ergometry (64 ± 3% VO_2peak) while ingesting 146 g carbohydrate. mTORC1 signaling (Western blotting) and gene transcription (RT-qPCR) were determined from vastus lateralis biopsies before glycogen depletion (baseline, BASE), and before (PRE) and after (POST) exercise.

Results

Regardless of treatment, p-mTORC1^Ser2448, p-p70S6K^Ser424/421, and p-rpS6^Ser235/236 were higher (P < 0.05) POST compared to PRE and BASE. PAX7 and MYOGENIN were lower (P < 0.05) in LOW compared to AD, regardless of time, while MYOD was lower (P < 0.05) in LOW compared to AD at PRE, but not different at POST.

Conclusion

Initiating aerobic exercise with low muscle glycogen does not affect mTORC1 signaling, yet reductions in gene expression of myogenic regulatory factors suggest that muscle recovery from exercise may be reduced.

Re-Evaluating the Oxidative Phenotype: Can Endurance Exercise Save the Western World?

Mitochondria are popularly called the "powerhouses" of the cell. They promote energy metabolism through the tricarboxylic acid (TCA) cycle and oxidative phosphorylation, which in contrast to cytosolic glycolysis are oxygen-dependent and significantly more substrate efficient. That is, mitochondrial metabolism provides substantially more cellular energy currency (ATP) per macronutrient metabolised. Enhancement of mitochondrial density and metabolism are associated with endurance training, which allows for the attainment of high relative VO2 max values. However, the sedentary lifestyle and diet currently predominant in the Western world lead to mitochondrial dysfunction. Underdeveloped mitochondrial metabolism leads to nutrient-induced reducing pressure caused by energy surplus, as reduced nicotinamide adenine dinucleotide (NADH)-mediated high electron flow at rest leads to "electron leak" and a chronic generation of superoxide radicals (O2-). Chronic overload of these reactive oxygen species (ROS) damages cell components such as DNA, cell membranes, and proteins. Counterintuitively, transiently generated ROS during exercise contributes to adaptive reduction-oxidation (REDOX) signalling through the process of cellular hormesis or "oxidative eustress" defined by Helmut Sies. However, the unaccustomed, chronic oxidative stress is central to the leading causes of mortality in the 21st century-metabolic syndrome and the associated cardiovascular comorbidities. The endurance exercise training that improves mitochondrial capacity and the protective antioxidant cellular system emerges as a universal intervention for mitochondrial dysfunction and resultant comorbidities. Furthermore, exercise might also be a solution to prevent ageing-related degenerative diseases, which are caused by impaired mitochondrial recycling. This review aims to break down the metabolic components of exercise and how they translate to athletic versus metabolically diseased phenotypes. We outline a reciprocal relationship between oxidative metabolism and inflammation, as well as hypoxia. We highlight the importance of oxidative stress for metabolic and antioxidant adaptation. We discuss the relevance of lactate as an indicator of critical exercise intensity, and inferring from its relationship with hypoxia, we suggest the most appropriate mode of exercise for the case of a lost oxidative identity in metabolically inflexible patients. Finally, we propose a reciprocal signalling model that establishes a healthy balance between the glycolytic/proliferative and oxidative/prolonged-ageing phenotypes. This model is malleable to adaptation with oxidative stress in exercise but is also susceptible to maladaptation associated with chronic oxidative stress in disease. Furthermore, mutations of components involved in the transcriptional regulatory mechanisms of mitochondrial metabolism may lead to the development of a cancerous phenotype, which progressively presents as one of the main causes of death, alongside the metabolic syndrome.

Evaluation of Measured Resting Metabolic Rate for Dietary Prescription in Ageing Adults with Overweight and Adiposity-Based Chronic Disease

The primary objective of this study was to compare weight changes in two groups of ageing Irish adults with overweight and adiposity-based chronic disease: participants who had dietary energy requirements prescribed on the base of measured RMR and participants whose RMR was estimated by a prediction equation. Fifty-four Caucasian adults (male n = 25; female n = 29, age 57.5 ± 6.3 years, weight 90.3 ± 15.1 kg, height 171.5 ± 9.5 cm, BMI 30.7 ± 4.6 kg/m²) were randomly assigned to a dietary intervention with energy prescription based on either measured RMR or estimated RMR. RMR was measured by indirect calorimetry after an overnight fast and predicted values were determined by the Mifflin et al. (1990) prediction equation. All participants received individual nutritional counselling, motivational interviewing and educational material. Anthropometric variables, blood pressure, blood glucose and blood lipid profile were assessed over 12 weeks. Body weight at week 12 was significantly lower (p < 0.05) for both groups following dietary interventions, mRMR: −4.2%; eRMR: −3.2% of initial body weight. There was no significant difference in weight loss between groups. Overall, 20.8% mRMR and 17.4% of eRMR participants experienced clinically meaningful (i.e., ≥5% of initial weight) weight reduction. Weight reduction in adults aged ≥50 years over the short term (12 weeks) favoured a reduction in blood pressure, triglycerides and glucose, thus reducing cardiovascular disease risk factors. This research indicates that employing a reduced-calorie diet using indirect calorimetry to determine energy needs when improving weight outcomes in adults (>50 years) with overweight and adiposity-based chronic disease is equal to employing a reduced-calorie diet based on the Mifflin et al. (1990) prediction equation. A reduced-energy diet based on mRMR or eRMR facilitates clinically meaningful weight reduction in adults (≥50 years) over the short term (12 weeks) and favours a reduction in blood pressure, triglycerides and glucose, thus reducing cardiovascular disease risk factors. Moreover, the addition of motivational interviewing and behaviour change techniques that support and encourage small behaviour changes is effective in short-term weight management.

The mediating role of adiposity in the longitudinal association between cardiorespiratory fitness and blood pressure in adolescents: LabMed cohort study

BACKGROUND

The aim of this prospective cohort study was to examine whether the association between the cardiorespiratory fitness (CRF) at baseline and blood pressure (BP) at follow-up is mediated by adiposity in adolescents.

MATERIALS AND METHODS

The sample comprised 734 adolescents (349 girls) aged 12-18 years from the LabMed Physical Activity Cohort Study. The variables of interest were measured in 2011 (baseline) and in 2013 (2-year follow-up). CRF was assessed by the 20-m shuttle run test. Body mass index, waist circumference, body fat percentage, pubertal status and resting BP were assessed according to standard procedures. Boot-strapped mediation procedures were performed, and indirect effects (IE) with confidence intervals (CI) not including zero were considered statistically significant.

RESULTS

After adjusting for potential confounders, body mass index acted as a mediator of the relationship between CRF and systolic BP (IE = -0. 023; CI = -0.039; -0.009), pulse pressure (IE = -0.023; CI = -0.034; -0.012) and rate product pressure (IE = -2.839; CI = -5.329; -0.340). Similar results were obtained for waist circumference as mediator for systolic BP (IE = -0.019; CI = -0.033; -0.005), pulse pressure (IE = -0.017; CI = -0.028; -0.007) and rate product pressure (IE = -3.793; CI = -6.097; -1.689). Likewise, body fat percentage mediated the association for: systolic BP (IE = -0.029; CI = -0.048; -0.010), pulse pressure (IE = -0.027; CI = -0.041; -0.013) and rate product pressure (IE = -4.280; CI = -7.488; -1.264).

CONCLUSIONS

Adiposity mediated the association between CRF and BP in adolescents. Therefore, both optimal CRF and adiposity levels are important to maintain normal BP ranges throughout adolescence.

Cholesterol was identified as a biomarker in human melanocytic nevi using DESI and DESI/PI mass spectrometry imaging

The rapid differentiation between diseased tissue and healthy normal tissue is of great importance for the intraoperative diagnosis. Herein, desorption electrospray ionization (DESI) and DESI/post-photoionization (DESI/PI) mass spectrometry imaging were combined to in situ visualize the distribution of biochemicals within the tissue regions of human melanocytic nevi under the ambient condition with a spatial resolution of around 200 μm. Plenty of polar and nonpolar lipids were found to be specifically distributed in melanocytic nevi with statistical significance and could be used to differentiate the healthy normal tissue and melanocytic nevi. Cholesterol was further confirmed to be a potential biomarker for melanocytic nevi diagnosis by multivariate statistical analysis and immunohistochemistry of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) and translocator protein (TSPO) enzymes. This work provides a visual way for the diagnosis of human melanocytic nevi by lipid profiling, which benefits the understanding of the pathological mechanism of melanocytic nevi and provides a new insight to control melanin growth from the synthesis, transport, and metabolism of cholesterol.

Performance determinants, running energetics and spatiotemporal gait parameters during a treadmill ultramarathon

Purpose

The objective of this study was to investigate the changes in metabolic variables, running energetics and spatiotemporal gait parameters during an 80.5 km treadmill ultramarathon and establish which key predictive variables best determine ultramarathon performance.

Methods

Twelve participants (9 male and 3 female, age 34 ± 7 years, and maximal oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O_2max) 60.4 ± 5.8 ml·kg⁻¹·min⁻¹) completed an 80.5 km time trial on a motorised treadmill in the fastest possible time. Metabolic variables: oxygen consumption (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O₂), carbon dioxide production (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙CO₂) and pulmonary ventilation (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙_E) were measured via indirect calorimetry every 16.1 km at a controlled speed of 8 km·h⁻¹ and used to calculate respiratory exchange ratio (RER), the energy cost of running (Cr) and fractional utilisation of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O_2max (F). Spatiotemporal gait parameters: stride length (SL) and cadence (SPM) were calculated via tri-axial accelerometery.

Results

Trial completion time was 09:00:18 ± 01:14:07 (hh:mm:ss). There were significant increases in \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙O₂, Cr, F, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}$$\end{document}V˙_E and heart rate (HR) (p < 0.01); a significant decrease in RER (p < 0.01) and no change in SL and SPM (p > 0.05) across the measured timepoints. F and Cr accounted for 61% of the variance in elapsed finish time (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$R_{{{\text{adj}}}}^{{2}}$$\end{document}Radj2 = 0.607, p < 0.01).

Conclusion

A treadmill ultramarathon elicits significant changes in metabolic variables, running energetics and spatiotemporal gait parameters. With F and Cr explaining 61% of variance in finish time. Therefore, those able to maintain a higher F, while adopting strategies to minimise an increase in Cr may be best placed to maximise ultramarathon performance.

Sport in Town: The Smart Healthy ENV Project, a Pilot Study of Physical Activity with Multiparametric Monitoring

Background: Increasing evidence links meteorological characteristics and air pollution to physiological responses during sports activities in urban areas with different traffic levels. Objective: The main objective of the Smart Healthy ENV (SHE, “Smart Monitoring Integrated System For A Healthy Urban Environment In Smart Cities”) project was to identify the specific responses of a group of volunteers during physical activity, by monitoring their heart rates and collecting breath samples, combined with data on meteorological determinants and pollution substances obtained through fixed sensor nodes placed along city routes and remotely connected to a dedicated data acquisition server. Methods: Monitoring stations were placed along two urban routes in Pisa, each two km long, with one located within the park beside the Arno river (green route) and the other in a crowded traffic zone (red route). Our sample participants were engaged in sports activities (N = 15, with different levels of ability) and were monitored through wearable sensors. They were first asked to walk back and forth (4 km) and then to run the same route. The experimental sessions were conducted over one day per route. A breath sample was also collected before each test. A questionnaire concerning temperature and fatigue perception was administered for all of the steps of the study over the two days. Results: The heart rates of the participants were monitored in the baseline condition, during walking, and while running, and were correlated with meteorological and pollutant data and with breath composition. Changes in the heart rates and breath composition were detected during the experimental sessions. These variations were related to the physical activity and to the meteorological conditions and air pollution levels. Conclusions: The SHE project can be considered a proof-of-concept study aimed at monitoring physiological and environmental variables during physical activity in urban areas, and can be used in future studies to provide useful information to those involved in sports and the broader community.

The major cap-binding protein eIF4E regulates lipid homeostasis and diet-induced obesity

Obesity is a global epidemic leading to increased mortality and susceptibility to comorbidities, with few viable therapeutic interventions. A hallmark of disease progression is the ectopic deposition of lipids in the form of lipid droplets in vital organs such as the liver. However, the mechanisms underlying the dynamic storage and processing of lipids in peripheral organs remain an outstanding question. Here, we show an unexpected function for the major cap-binding protein, eIF4E, in high-fat-diet-induced obesity. In response to lipid overload, select networks of proteins involved in fat deposition are altered in eIF4E-deficient mice. Specifically, distinct messenger RNAs involved in lipid metabolic processing and storage pathways are enhanced at the translation level by eIF4E. Failure to translationally upregulate these mRNAs results in increased fatty acid oxidation, which enhances energy expenditure. We further show that inhibition of eIF4E phosphorylation genetically-and by a potent clinical compound-restrains weight gain following intake of a high-fat diet. Together, our study uncovers translational control of lipid processing as a driver of high-fat-diet-induced weight gain and provides a pharmacological target to treat obesity.

The importance of protein intake in master marathon runners

OBJECTIVES

The aim of this study was to investigate the relationships between protein intake (during the tapering period and the race), marathon performance, body composition, acute race-induced changes, and selected metabolic- and muscle damage-related blood biomarkers in recreational master runners.

METHODS

In 58 experienced master runners (58.28 y ± 1.07 y, 174.06 cm ± 0.72 cm, 78.51 kg ± 0.76 kg body mass, 21.38% ± 0.52% body fat, mean ± SEM), nutritional intake was evaluated 1 wk before the race and during the marathon. Body composition was evaluated before and 2 h after the race. Blood samples were collected at the same time points.

RESULTS

Body fat and lean body mass (LBM) were significantly reduced after the marathon (P < 0.01; η²: 0.311-0.888). Significant negative correlations were observed between energy intake from carbohydrates and proteins (expressed per LBM), marathon performance, and race-induced changes of blood metabolic-muscle damage indices (P < 0.05; r: -0.522 to -0.789). Positive correlations were observed between energy from carbohydrates and proteins per LBM, and body mass and LBM changes (P < 0.05; r: 0.485-0.814). The specific contribution of protein intakes per LBM (beta coefficient: -0.789 to 0.615) on race-induced changes of body composition and blood markers was the same as that of carbohydrate intakes per LBM (beta coefficient: -0.777 to 0.559).

CONCLUSIONS

Marathon-induced changes in body composition and metabolic blood indices are highly related to protein intake, either during the tapering period or during the race, with runners experiencing the lowest changes when consuming higher protein intakes.

Zumba®, Fat Mass and Maximum Oxygen Consumption: A Systematic Review and Meta-Analysis

Background and objectives: Obesity or overweight is associated with many health risk factors and preventable mortality. Even people with normal weight and without history of obesity or overweight should avoid weight gain to reduce health risks factors. In this regard Latin aerobic dances involved in Zumba^® practice make this modality motivating for people. Apart from weight loss and VO2_peak benefits, Zumba practice is also interesting by the increase in adherence which can also avoid weight regain. The aim was to systematically review the scientific literature about the effects of any randomized intervention of Zumba^® practice on total fat mass (%) and maximum oxygen consumption (VO_2peak), besides establishing directions for the clinical practice. Evidence acquisition: Two systematic searches were conducted in two electronic databases following the PRISMA guidelines. The eligibility criteria were (a) outcomes: body mass or VO_2peak data including mean and standard deviation (SD) before and after Zumba^® intervention, (b) study design: randomized controlled trial (RCT) and (c) language: English. GRADE guidelines were used to assess the quality of evidence. A meta-analysis was performed to determine mean differences. Nine and four studies were selected for fat mass percentage and VO_2peak in the systematic review, respectively. However, only eight studies for fat mass percentage and three for VO_2peak could be included in the meta-analysis. Evidence synthesis: The overall standardized mean difference for fat mass was −0.25 with a 95% CI from −0.67 to 0.16 with a p-value of 0.69, with large heterogeneity. On the other hand, the overall effect size for VO_2peak was 0.53 (95% CI from 0.04 to 1.02 with a p-value of 0.03) with large heterogeneity. Conclusions: Based on the evidence, we cannot conclude that Zumba^® is effective at reducing body mass but it may improve VO_2peak. However, the limited number of studies that met the inclusion criteria makes it too early to reach a definite conclusion, so more research is needed.