Aerobic fitness determines whole-body fat oxidation rate during exercise in the heat

2010 ◽  
Vol 35 (6) ◽  
pp. 741-748 ◽  
Author(s):  
Juan Del Coso ◽  
Nassim Hamouti ◽  
Juan Fernando Ortega ◽  
Ricardo Mora-Rodriguez
Keyword(s):  
Oxygen Uptake ◽  
Body Fat ◽  
Healthy Subjects ◽  
Fat Oxidation ◽  
Exercise Duration ◽  
Substrate Oxidation ◽  
Peak Oxygen Uptake ◽  
Total Energy Expenditure ◽  
Whole Body ◽  
Blood Samples

The purpose of this study was to determine whole-body fat oxidation in endurance-trained (TR) and untrained (UNTR) subjects exercising at different intensities in the heat. On 3 occasions, 10 TR cyclists and 10 UNTR healthy subjects (peak oxygen uptake = 60 ± 6 vs. 44 ± 3 mL·kg–1·min–1; p < 0.05) exercised at 40%, 60%, and 80% peak oxygen uptake in a hot, dry environment (36 °C; 25% relative humidity). To complete the same amount of work in all 3 trials, exercise duration varied (107 ± 4, 63 ± 1, and 45 ± 0 min for 40%, 60%, and 80% peak oxygen uptake, respectively). Substrate oxidation was calculated using indirect calorimetry. Blood samples were collected at the end of exercise to determine plasma epinephrine ([EPI]plasma) and norepinephrine ([NEPI]plasma) concentrations. The maximal rate of fat oxidation was achieved at 60% peak oxygen uptake for the TR group (0.41 ± 0.01 g·min–1) and at 40% peak oxygen uptake for the UNTR group (0.28 ± 0.01 g·min–1). TR subjects oxidized absolutely (g·min–1) and relatively (% of total energy expenditure) more fat than UNTR subjects at 60% and 80% peak oxygen uptake (p < 0.05). At these exercise intensities, TR subjects also had higher [NEPI]plasma concentrations than UNTR subjects (p < 0.05). In the heat, whole-body peak fat oxidation occurs at higher relative exercise intensities in TR than in UNTR subjects (60% vs. 40% peak oxygen uptake). Moreover, TR subjects oxidize more fat than UNTR subjects when exercising at moderate to high intensities (>60% peak oxygen uptake).

Gender differences in whole-body fat oxidation kinetics during exercise

2011 ◽  
Vol 36 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Xavier Chenevière ◽  
Fabio Borrani ◽  
David Sangsue ◽  
Boris Gojanovic ◽  
Davide Malatesta
Keyword(s):  
Oxygen Uptake ◽  
Body Fat ◽  
Maximal Oxygen Uptake ◽  
Oxidation Kinetics ◽  
Fat Oxidation ◽  
Whole Body ◽  
Maximal Power ◽  
Maximal Power Output ◽  
Men And Women ◽  
Oxidation Rates

Discrepancies appear in studies comparing fat oxidation between men and women. Therefore, this study aimed to quantitatively describe and compare whole-body fat oxidation kinetics between genders during exercise, using a sinusoidal (SIN) model. Twelve men and 11 women matched for age, body mass index, and aerobic fitness (maximal oxygen uptake and maximal power output per kilogram of fat-free mass (FFM)) performed submaximal incremental tests (Incr) with 5-min stages and a 7.5% maximal power output increment on a cycle ergometer. Fat oxidation rates were determined using indirect calorimetry, and plotted as a function of exercise intensity. The SIN model, which includes 3 independent variables (dilatation, symmetry, translation) that account for the main quantitative characteristics of kinetics, was used to mathematically describe fat oxidation kinetics and to determine the intensity (Fatmax) eliciting the maximal fat oxidation (MFO). During Incr, women exhibited greater fat oxidation rates from 35% to 85% maximal oxygen uptake, MFO (6.6 ± 0.9 vs. 4.5 ± 0.3 mg·kg FFM−1·min−1), and Fatmax (58.1% ± 1.9% vs. 50.0% ± 2.7% maximal oxygen uptake) than men (p < 0.05). While men and women showed similar global shapes of fat oxidation kinetics in terms of dilatation and symmetry (p > 0.05), the fat oxidation curve tended to be shifted toward higher exercise intensities in women (rightward translation, p = 0.08). These results support the idea that women have a greater reliance on fat oxidation than men during submaximal exercise, but also indicate that this greater fat oxidation is shifted toward higher exercise intensities in women than in men.

Fat Utilization in Healthy Subjects Consuming Diacylglycerol Oil Diet: Dietary and Whole Body Fat Oxidation

Lipids ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 517-524 ◽  
Author(s):  
Masanobu Hibi ◽  
Hideto Takase ◽  
Koichi Yasunaga ◽  
Tohru Yamaguchi ◽  
Ushio Harada ◽  
...  
Keyword(s):  
Body Fat ◽  
Healthy Subjects ◽  
Fat Oxidation ◽  
Whole Body ◽  
Fat Utilization ◽  
Diacylglycerol Oil

scholarly journals Nutritional ketone salts increase fat oxidation but impair high-intensity exercise performance in healthy adult males

2017 ◽  
Vol 42 (10) ◽  
pp. 1031-1035 ◽  
Author(s):  
Trevor O’Malley ◽  
Etienne Myette-Cote ◽  
Cody Durrer ◽  
Jonathan P. Little
Keyword(s):  
Steady State ◽  
Oxygen Uptake ◽  
Exercise Performance ◽  
Healthy Adult ◽  
Time Trial ◽  
Fat Oxidation ◽  
Substrate Oxidation ◽  
Peak Oxygen Uptake ◽  
Adult Males ◽  
Cycling Exercise

This study investigated the impact of raising plasma beta-hydroxybutyrate (β-OHB) through ingestion of ketone salts on substrate oxidation and performance during cycling exercise. Ten healthy adult males (age, 23 ± 3 years; body mass index, 25 ± 3 kg/m2, peak oxygen uptake, 45 ± 10 mL/(kg·min)−1) were recruited to complete 2 experimental trials. Before enrollment in the experimental conditions, baseline anthropometrics and cardiorespiratory fitness (peak oxygen uptake) were assessed and familiarization to the study protocol was provided. On experimental days, participants reported to the laboratory in the fasted state and consumed either 0.3 g/kg β-OHB ketone salts or a flavour-matched placebo at 30 min prior to engaging in cycling exercise. Subjects completed steady-state exercise at 30%, 60%, and 90% ventilatory threshold (VT) followed by a 150-kJ cycling time-trial. Respiratory exchange ratio (RER) and total substrate oxidation were derived from indirect calorimetry. Plasma glucose, lactate, and ketones were measured at baseline, 30 min post-supplement, post–steady-state exercise, and immediately following the time-trial. Plasma β-OHB was elevated from baseline and throughout the entire protocol in the ketone condition (p < 0.05). RER was lower at 30% and 60% VT in the ketone compared with control condition. Total fat oxidation was greater in the ketone versus control (p = 0.05). Average time-trial power output was ∼7% lower (–16 W, p = 0.029) in the ketone condition. Ingestion of ketone salts prior to exercise increases fat oxidation during steady-state exercise but impairs high-intensity exercise performance.

Prolonged exercise after diuretic-induced hypohydration: effects on substrate turnover and oxidation

2000 ◽  
Vol 279 (6) ◽  
pp. E1383-E1390 ◽  
Author(s):  
B. D. Roy ◽  
H. J. Green ◽  
M. Burnett
Keyword(s):  
Oxygen Uptake ◽  
Specific Effect ◽  
Fat Oxidation ◽  
Peak Oxygen Uptake ◽  
Whole Body ◽  
Moderate Intensity ◽  
Glucose Kinetics ◽  
Total Carbohydrate ◽  
Serum Free Fatty Acid ◽  
Young Males

To determine the influence of a diuretic-induced reduction in plasma volume (PV) on substrate turnover and oxidation, 10 healthy young males were studied during 60 min of cycling exercise at 61% peak oxygen uptake on two separate occasions ≥1 wk apart. Exercise was performed under control conditions (CON; placebo), and after 4 days of diuretic administration (DIU; Novotriamazide; 100 mg triamterene and 50 mg hydrochlorothiazide). DIU resulted in a calculated reduction of PV by 14.6 ± 3.3% ( P < 0.05). Rates of glucose appearance (Ra) and disappearance (Rd) and glycerol Ra were determined by using primed constant infusions of [6,6-2H]glucose and [2H5]glycerol, respectively. No differences in oxygen uptake during exercise were observed between trials. Main effects for condition ( P < 0.05) were observed for plasma glucose and glycerol, such that the values observed for DIU were higher than for CON. No differences were observed in plasma lactate and serum free fatty acid concentrations either at rest or during exercise. Hypohydration led to lower ( P < 0.05) glucose Ra and Rd at rest and at 15 and 30 min of exercise, but by 60 min, the effects were reversed ( P < 0.05). Hypohydration had no effect on rates of whole body lipolysis or total carbohydrate or fat oxidation. A main effect for condition ( P < 0.05) was observed for plasma glucagon concentrations such that larger values were observed for DIU than for CON. A similar decline in plasma insulin occurred with exercise in both conditions. These results indicate that diuretic-induced reductions in PV decreases glucose kinetics during moderate-intensity dynamic exercise in the absence of changes in total carbohydrate and fat oxidation. The specific effect on glucose kinetics depends on the duration of the exercise.

scholarly journals Whole-body fat oxidation increases more by prior exercise than overnight fasting in elite endurance athletes

2016 ◽  
Vol 41 (4) ◽  
pp. 430-437 ◽  
Author(s):  
Ulrika Andersson Hall ◽  
Fredrik Edin ◽  
Anders Pedersen ◽  
Klavs Madsen
Keyword(s):  
Oxygen Uptake ◽  
Body Fat ◽  
Maximal Oxygen Uptake ◽  
Fat Oxidation ◽  
Endurance Athletes ◽  
Whole Body ◽  
Oxidation Rates ◽  
Prior Exercise ◽  
Overnight Fasting ◽  
Maximal Fat Oxidation

The purpose of this study was to compare whole-body fat oxidation kinetics after prior exercise with overnight fasting in elite endurance athletes. Thirteen highly trained athletes (9 men and 4 women; maximal oxygen uptake: 66 ± 1 mL·min−1·kg−1) performed 3 identical submaximal incremental tests on a cycle ergometer using a cross-over design. A control test (CON) was performed 3 h after a standardized breakfast, a fasting test (FAST) 12 h after a standardized evening meal, and a postexercise test (EXER) after standardized breakfast, endurance exercise, and 2 h fasting recovery. The test consisted of 3 min each at 30%, 40%, 50%, 60%, 70%, and 80% of maximal oxygen uptake and fat oxidation rates were measured through indirect calorimetry. During CON, maximal fat oxidation rate was 0.51 ± 0.04 g·min−1 compared with 0.69 ± 0.04 g·min−1 in FAST (P < 0.01), and 0.89 ± 0.05 g·min−1 in EXER (P < 0.01). Across all intensities, EXER was significantly higher than FAST and FAST was higher than CON (P < 0.01). Blood insulin levels were lower and free fatty acid and cortisol levels were higher at the start of EXER compared with CON and FAST (P < 0.05). Plasma nuclear magnetic resonance-metabolomics showed similar changes in both EXER and FAST, including increased levels of fatty acids and succinate. In conclusion, prior exercise significantly increases whole-body fat oxidation during submaximal exercise compared with overnight fasting. Already high rates of maximal fat oxidation in elite endurance athletes were increased by approximately 75% after prior exercise and fasting recovery.

Determinants of maximal whole-body fat oxidation in elite cross-country skiers: Role of skeletal muscle mitochondria

2018 ◽  
Vol 28 (12) ◽  
pp. 2494-2504 ◽  
Author(s):  
Sune Dandanell ◽  
Anne-Kristine Meinild-Lundby ◽  
Andreas B. Andersen ◽  
Paul F. Lang ◽  
Laura Oberholzer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Fat ◽  
Fat Oxidation ◽  
Whole Body ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Cross Country

scholarly journals Increasing skeletal muscle carnitine content in older individuals increases whole‐body fat oxidation during moderate‐intensity exercise

Aging Cell ◽  
2021 ◽  
Vol 20 (2) ◽  
Author(s):  
Carolyn Chee ◽  
Chris E. Shannon ◽  
Aisling Burns ◽  
Anna L. Selby ◽  
Daniel Wilkinson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Fat ◽  
Fat Oxidation ◽  
Whole Body ◽  
Moderate Intensity ◽  
Older Individuals ◽  
Moderate Intensity Exercise

Reduced plasma FFA availability increases net triacylglycerol degradation, but not GPAT or HSL activity, in human skeletal muscle

2004 ◽  
Vol 287 (1) ◽  
pp. E120-E127 ◽  
Author(s):  
Matthew J. Watt ◽  
Anna G. Holmes ◽  
Gregory R. Steinberg ◽  
Jose L. Mesa ◽  
Bruce E. Kemp ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Body Fat ◽  
Plasma Free Fatty Acid ◽  
Fat Oxidation ◽  
Dry Mass ◽  
Hormone Sensitive Lipase ◽  
Whole Body ◽  
Plasma Ffa

Intramuscular triacylglycerols (IMTG) are proposed to be an important metabolic substrate for contracting muscle, although this remains controversial. To test the hypothesis that reduced plasma free fatty acid (FFA) availability would increase IMTG degradation during exercise, seven active men cycled for 180 min at 60% peak pulmonary O2 uptake either without (CON) or with (NA) prior ingestion of nicotinic acid to suppress adipose tissue lipolysis. Skeletal muscle and adipose tissue biopsy samples were obtained before and at 90 and 180 min of exercise. NA ingestion decreased ( P < 0.05) plasma FFA at rest and completely suppressed the exercise-induced increase in plasma FFA (180 min: CON, 1.42 ± 0.07; NA, 0.10 ± 0.01 mM). The decreased plasma FFA during NA was associated with decreased ( P < 0.05) adipose tissue hormone-sensitive lipase (HSL) activity (CON: 13.9 ± 2.5, NA: 9.1 ± 3.0 nmol·min−1·mg protein−1). NA ingestion resulted in decreased whole body fat oxidation and increased carbohydrate oxidation. Despite the decreased whole body fat oxidation, net IMTG degradation was greater in NA compared with CON (net change: CON, 2.3 ± 0.8; NA, 6.3 ± 1.2 mmol/kg dry mass). The increased IMTG degradation did not appear to be due to reduced fatty acid esterification, because glycerol 3-phosphate activity was not different between trials and was unaffected by exercise (rest: 0.21 ± 0.07; 180 min: 0.17 ± 0.04 nmol·min−1·mg protein−1). HSL activity was not increased from resting rates during exercise in either trial despite elevated plasma epinephrine, decreased plasma insulin, and increased ERK1/2 phosphorylation. AMP-activated protein kinase (AMPK)α1 activity was not affected by exercise or NA, whereas AMPKα2 activity was increased ( P < 0.05) from rest during exercise in NA and was greater ( P < 0.05) than in CON at 180 min. These data suggest that plasma FFA availability is an important mediator of net IMTG degradation, and in the absence of plasma FFA, IMTG degradation cannot maintain total fat oxidation. These changes in IMTG degradation appear to disassociate, however, from the activity of the key enzymes responsible for synthesis and degradation of this substrate.

scholarly journals Ultra Trail Performance is Differently Predicted by Endurance Variables in Men and Women

2020 ◽  
Author(s):  
Ignacio Martinez-Navarro ◽  
Antonio Montoya-Vieco ◽  
Eladio Collado ◽  
Bárbara Hernando ◽  
Carlos Hernando
Keyword(s):  
Oxygen Uptake ◽  
Female Athletes ◽  
Fat Oxidation ◽  
Peak Oxygen Uptake ◽  
Significant Variable ◽  
Men And Women ◽  
Male And Female ◽  
Race Time ◽  
Maximal Fat Oxidation ◽  
Peak Speed

AbstractThe study aimed to assess the relationship between peak oxygen uptake, ventilatory thresholds and maximal fat oxidation with ultra trail male and female performance. 47 athletes (29 men and 18 women) completed a cardiopulmonary exercise test between 2 to 4 weeks before a 107-km ultra trail. Body composition was also analyzed using a bioelectrical impedance weight scale. Exploratory correlation analyses showed that peak oxygen uptake (men: r=–0.63, p=0.004; women: r=–0.85, p < 0.001), peak speed (men: r=–0.74, p < 0.001; women: r=–0.69, p=0.009), speed at first (men: r=–0.49, p=0.035; women: r=–0.76, p=0.003) and second (men: r=–0.73, p < 0.001; women: r=–0.76, p=0.003) ventilatory threshold, and maximal fat oxidation (men: r=–0.53, p=0.019; women: r=–0.59, p=0.033) were linked to race time in male and female athletes. Percentage of fat mass (men: r=0.58, p=0.010; women: r=0.62, p= 0.024) and lean body mass (men: r=–0.61, p=0.006; women: r=–0.61, p=0.026) were also associated with performance in both sexes. Subsequent multiple regression analyses revealed that peak speed and maximal fat oxidation together were able to predict 66% of male performance; while peak oxygen uptake was the only statistically significant variable explaining 69% of the variation in women’s race time. These results, although exploratory in nature, suggest that ultra trail performance is differently predicted by endurance variables in men and women.

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