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

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

SUBMITTER: Croci I

PROVIDER: S-EPMC4041727 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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

Croci Ilaria I Borrani Fabio F Byrne Nuala M NM Wood Rachel E RE Hickman Ingrid J IJ Chenevière Xavier X Malatesta Davide D

PloS one 20140602 6

Aerobic exercise training performed at the intensity eliciting maximal fat oxidation (Fat(max)) has been shown to improve the metabolic profile of obese patients. However, limited information is available on the reproducibility of Fat(max) and related physiological measures. The aim of this study was to assess the intra-individual variability of: a) Fat(max) measurements determined using three different data analysis approaches and b) fat and carbohydrate oxidation rates at rest and at each stag ...[more]

PMID: 24886715

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Project description:The purpose of this investigation was to compare changes in circulating lymphocyte subset cell counts between high-intensity interval exercise (HIIE), sprint interval exercise (SIE), and moderate-intensity continuous exercise (MICE). Recreationally active men (n = 11; age: 23 ± 4 yr; height: 179.9 ± 4.5 cm; body mass: 79.8 ± 8.7 kg; body fat %:12.6 ± 3.8%; V̇O2max: 46.6 ± 3.9 ml⋅kg-1⋅min-1) completed a maximal graded exercise test to determine maximal oxygen uptake (V̇O2max) and three duration-matched cycling trials (HIIE, SIE, and MICE) in a randomized, counterbalanced fashion. HIIE consisted of fifteen 90-s bouts at 85% V̇O2max interspersed with 90-s active recovery periods. SIE consisted of fifteen 20-s bouts at 130% maximal power and 160-s active recovery periods. MICE was a continuous bout at 65% V̇O2max. Total exercise duration was 53 min in all three trials, including warm-up and cool-down. Blood was collected before, immediately post, 30 min, 2 h, 6 h, and 24 h post-exercise. Changes in lymphocyte subset counts, and surface expression of various markers were analyzed via flow cytometry. Changes were assessed using mixed model regression analysis with an autoregressive first order repeated measures correction. Significant decreases were observed in absolute counts of CD56dim NK cells, CD19+ B cells, CD4+ T cells, and CD8+ T cells 30 min and 24-h post-exercise in all three trials. Despite resulting in greater total work and oxygen consumption, MICE elicited similar changes in lymphocyte subset counts and receptor expression compared to both SIE and HIIE. Similarly, while the two interval trials resulted in differing oxygen consumption and total work, no differences in the lymphocyte response were observed. Though both forms of exercise resulted in declines in circulating lymphocyte cell counts, neither exercise type provides an immune-related advantage when matched for duration.

Project description:Purpose:The present study aimed to determine whether whole-body fat oxidation and muscle deoxygenation kinetics parameters during exercise were related in individuals with different aerobic fitness levels. Methods:Eleven cyclists [peak oxygen uptake ( V.O2?p?e?a?k ): 64.9 ± 3.9 mL?kg-1?min-1] and 11 active individuals ( V.O2?p?e?a?k : 49.1 ± 7.4 mL?kg-1?min-1) performed a maximal incremental cycling test to determine V.O2?p?e?a?k and a submaximal incremental cycling test to assess whole-body fat oxidation using indirect calorimetry and muscle deoxygenation kinetics of the vastus lateralis (VL) using near-infrared spectroscopy (NIRS). A sinusoidal (SIN) model was used to characterize fat oxidation kinetics and to determine the intensity (Fatmax) eliciting maximal fat oxidation (MFO). The muscle deoxygenation response was fitted with a double linear model. The slope of the first parts of the kinetics (a 1) and the breakpoint ([HHb]BP) were determined. Results:MFO (p = 0.01) and absolute fat oxidation rates between 20 and 65% V.O2?p?e?a?k were higher in cyclists than in active participants (p < 0.05), while Fatmax occurred at a higher absolute exercise intensity (p = 0.01). a 1 was lower in cyclists (p = 0.02) and [HHb]BP occurred at a higher absolute intensity (p < 0.001) than in active individuals. V.O2?p?e?a?k was strongly correlated with MFO, Fatmax, and [HHb]BP (r = 0.65-0.88, p ? 0.001). MFO and Fatmax were both correlated with [HHb]BP (r = 0.66, p = 0.01 and r = 0.68, p < 0.001, respectively) and tended to be negatively correlated with a 1 (r = -0.41, p = 0.06 for both). Conclusion:This study showed that whole-body fat oxidation and muscle deoxygenation kinetics were both related to aerobic fitness and that a relationship between the two kinetics exists. Individuals with greater aerobic fitness may have a delayed reliance on glycolytic metabolism at higher exercise intensities because of a longer maintained balance between O2 delivery and consumption supporting higher fat oxidation rates.

Project description:A single nucleotide polymorphism (SNP) in the fat mass and obesity-associated (FTO) gene is a strong predictor of obesity in humans. The FTO SNP (rs1421085) results in a T to C nucleotide substitution that may result in an increased risk for obesity in individuals who carry at least one C allele. The purpose of this investigation was to characterize the FTO genotype in a cohort of exercise-trained men and women.We tested 108 exercise-trained individuals that included professional mixed martial arts fighters, competitive distance runners, collegiate swimmers, stand-up paddlers as well as a cohort of recreational bodybuilders. Body composition was assessed via dual-energy x-ray absorptiometry (DXA). Saliva samples were collected in order to genotype participants and quantify cortisol levels.The physical characteristics of the subjects were as follows (mean±SD): body weight 74.5±15.6 kg; height 171.5±9.5 cm; bone mineral content 2.8±0.7 kg; fat mass 15.7±5.5 kg; lean body mass 55.9±14.4 kg; % body fat 21.6±7.0. Independent samples t tests showed that C allele carriers (n =?54) had significantly higher fat mass t(106)?=?3.13, p <?0.01 and body fat percentage t(106)?=?2.68, p?<?0.01, relative to the TT group (n?=?54) (i.e., fat mass: C/-?17.3 ±5.6 kg, TT 14.2±4.6 kg; body fat percentage: C/- group 23.4±7.4%, TT group 19.9±6.2). No other measures of body composition were associated with the FTO genotype (i.e., body mineral density, bone mineral content, or lean body mass). Moreover, cortisol levels were significantly higher in the TT group relative to the C allele carriers t(106)?=?2.37, p =?0.02 (i.e., TT 0.35 ±0.35 ?g/dL, C/-?0.22±0.16 ?g/dL).Our findings demonstrate a relationship between C allele carriers on the FTO gene and a predisposition to a higher fat mass and body fat percentage. In addition, we found no relationship between cortisol and fat mass. However, due to the cross-sectional nature of this investigation, we cannot infer causality regarding the FTO gene and body composition.

Project description:Background: Substantial interindividual variability exists in the maximal rate of fat oxidation (MFO) during exercise with potential implications for metabolic health. Although the diet can affect the metabolic response to exercise, the contribution of a self-selected diet to the interindividual variability in the MFO requires further clarification.Objective: We sought to identify whether recent, self-selected dietary intake independently predicts the MFO in healthy men and women.Design: The MFO and maximal oxygen uptake ([Formula: see text]O2 max) were determined with the use of indirect calorimetry in 305 healthy volunteers [150 men and 155 women; mean ± SD age: 25 ± 6 y; body mass index (BMI; in kg/m2): 23 ± 2]. Dual-energy X-ray absorptiometry was used to assess body composition with the self-reported physical activity level (SRPAL) and dietary intake determined in the 4 d before exercise testing. To minimize potential confounding with typically observed sex-related differences (e.g., body composition), predictor variables were mean-centered by sex. In the analyses, hierarchical multiple linear regressions were used to quantify each variable's influence on the MFO.Results: The mean absolute MFO was 0.55 ± 0.19 g/min (range: 0.19-1.13 g/min). A total of 44.4% of the interindividual variability in the MFO was explained by the [Formula: see text]O2 max, sex, and SRPAL with dietary carbohydrate (carbohydrate; negative association with the MFO) and fat intake (positive association) associated with an additional 3.2% of the variance. When expressed relative to fat-free mass (FFM), the MFO was 10.8 ± 3.2 mg · kg FFM-1 · min-1 (range: 3.5-20.7 mg · kg FFM-1 · min-1) with 16.6% of the variability explained by the [Formula: see text]O2 max, sex, and SRPAL; dietary carbohydrate and fat intakes together explained an additional 2.6% of the variability. Biological sex was an independent determinant of the MFO with women showing a higher MFO [men: 10.3 ± 3.1 mg · kg FFM-1 · min-1 (3.5-19.9 mg · kg FFM-1 · min-1); women: 11.2 ± 3.3 mg · kg FFM-1 · min-1 (4.6-20.7 mg · kg FFM-1 · min-1); P < 0.05].Conclusion: Considered alongside other robust determinants, dietary carbohydrate and fat intake make modest but independent contributions to the interindividual variability in the capacity to oxidize fat during exercise. This trial was registered at clinicaltrials.gov as NCT02070055.

Project description:BACKGROUND:There are animal data suggesting green tea can enhance blood flow. However, human data are lacking. Thus, the purpose of this study was to examine the acute effects of low and high doses of a green tea-based supplement (GBS) on brachial artery blood flow before and following a resistance exercise bout. METHODS:In this, double-blinded placebo-controlled trial, college-aged males (n?=?18) who self-reported recreationally resistance training for the previous 6?±?3?years were assigned to one of two studies including a low (300?mg serving) (n?=?9) or high dose (600?mg serving) (n?=?8; 1 drop) GBS study. During testing sessions, participants reported to the laboratory following an overnight fast and rested in a supine position for 15?min. Thereafter, baseline measurements for resting heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), brachial artery diameter (BAD) and blood flow (BBF) were obtained (PRE). Participants then consumed either their respective GBS dose or a similar placebo dose (microcrystalline cellulose) in a supine resting state. HR, SBP, DBP, BAD and BBF were measured 45?min after placebo or GBS ingestion (PRE2). Participants were then placed in a recumbent position and performed 4 sets of 10 arm curl repetitions using an 11?kg dumbbell. Participants returned to a supine position and HR, SBP, DBP, BAD and BBF were obtained within the first 3?min following exercise (POST), 15?min after exercise (15POST), and 45?min after exercise (45POST). Participants returned to the laboratory 24-48?h later to repeat the same protocol with either GBS or the placebo depending on randomization. Two-way (supplement x time) repeated measures ANOVAs were used to compare dependent variables between testing sessions for Study 1 (300?mg of GBS and placebo) and Study 2 (600?mg of GBS and placebo), and statistical significance was set at p?<?0.05. No statistical comparisons were made between studies. RESULTS:As expected, exercise increased BAD and BBF compared to resting baseline measured irrespective of supplementation. In addition, BAD and BBF did not differ between GBS and placebo at any time point after exercise in Study 1. In study 2, however, 600?mg GBS increased baseline-normalized BBF at immediately post exercise compared to placebo (placebo?=?211?±?155% increase, GBS?=?349?±?156% increase; p?=?0.012) but not BAD. CONCLUSIONS:These data suggest a higher dose of GBS can enhance localized blood flow acutely following a resistance exercise bout. However, the long-term implications of these data are unclear, and more well-powered studies are needed to validate efficacy and elucidate potential mechanisms.

Dataset Information

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

Publications

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

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