Endurance training increases fatty acid turnover,  but not fat oxidation, in young men

Friedlander, Anne L.; Casazza, Gretchen A.; Horning, Michael A.; Ušaj, Anton; Brooks, George A.

doi:10.1152/jappl.1999.86.6.2097

Cited by 104 publications

(123 citation statements)

References 27 publications

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“…In lean subjects, the effects of exercise training on fat metabolism at rest are not consistent. Some studies reported an increased fat oxidation at rest after exercise training (5,30,31), whereas others found no change (9,10,38). Cross-sectional studies comparing trained and untrained lean subjects at rest showed higher fat oxidation rates in trained compared with untrained subjects (21,33,44).…”

Section: Discussionmentioning

confidence: 99%

Effect of exercise training at different intensities on fat metabolism of obese men

Aggel-Leijssen

Saris

Wagenmakers

et al. 2002

Journal of Applied Physiology

111

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. Effect of exercise training at different intensities on fat metabolism of obese men. J Appl Physiol 92: 1300-1309, 2002; 10.1152/japplphysiol.00030.2001.-The present study investigated the effect of exercise training at different intensities on fat oxidation in obese men. Twenty-four healthy male obese subjects were randomly divided in either a low-[40% maximal oxygen consumption (V O2 max)] or high-intensity exercise training program (70% V O2 max) for 12 wk, or a nonexercising control group. Before and after the intervention, measurements of fat metabolism at rest and during exercise were performed by using indirect calorimetry, [U-13 C]palmitate, and [1,2-13 C]acetate. Furthermore, body composition and maximal aerobic capacity were measured. Total fat oxidation did not change at rest in any group. During exercise, after low-intensity exercise training, fat oxidation was increased by 40% (P Ͻ 0.05) because of an increased non-plasma fatty acid oxidation (P Ͻ 0.05). Highintensity exercise training did not affect total fat oxidation during exercise. Changes in fat oxidation were not significantly different among groups. It was concluded that lowintensity exercise training in obese subjects seemed to increase fat oxidation during exercise but not at rest. No effect of high-intensity exercise training on fat oxidation could be shown. low intensity; stable isotopes; acetate correction factor; [ 13 C]palmitate OBESITY IS ASSOCIATED with an impaired ability to use fat as a fuel. This may contribute to the development and maintenance of large fat stores. Upper body obesity is associated with an impaired postabsorptive free fatty acid (FFA) utilization in skeletal muscle in women (6). Isoprenaline-induced fat oxidation and skeletal muscle FFA uptake are impaired in obese men, and no improvement was found after weight loss (1-3). Lean, formerly obese women have lower fasting fat oxidation rates compared with lean, never-obese women (32). Moreover, in Pima Indians, a population with a high prevalence of obesity, weight gain is association with a low 24-h fat-to-carbohydrate oxidation ratio (49). Several explanations have been proposed for this reduced fat utilization in obesity, such as a low activity of enzymes of ␤-oxidation (50), low skeletal muscle lipoprotein lipase activity (7), and impaired mobilization of fat stores (1). Interventions that will increase the capacity of the skeletal muscle to utilize fat may, therefore, make an important contribution to weight management in obese individuals and individuals at risk for obesity.Endurance exercise training is known to increase fat oxidation during submaximal exercise at a fixed workload in lean subjects (14,17,23,30,38). Cross-sectional studies also report higher fat oxidation during exercise after an overnight fast (18,20,21,40,45) or with glucose (19, 47) in trained compared with sedentary men. Some studies also found an enhanced resting fat oxidation after endurance training (5, 31, 34). Thus endurance exercise training appears to have the capacity to increase ...

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Section: Discussionmentioning

confidence: 99%

Effect of exercise training at different intensities on fat metabolism of obese men

Aggel-Leijssen

Saris

Wagenmakers

et al. 2002

Journal of Applied Physiology

111

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“…durante 60 minutos com período de repouso semelhante entre uma sessão e outra) são mais eficientes na mobilização dos AG do que apenas uma sessão de esforço físico. No caso do treinamento, é observado um aumento na concentração plasmática de AG, porém a oxidação desses nos músculos esqueléticos depende da intensidade relativa do esforço (15).…”

Section: Mobilização E Captação Dos áCidos Graxos Nos Músculos Esquelunclassified

Ciclo de Krebs como fator limitante na utilização de ácidos graxos durante o exercício aeróbico

Curi

Lagranha

Rodrigues

et al. 2003

Arq Bras Endocrinol Metab

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RESUMOOs ácidos graxos (AG) representam uma fonte importante de energia durante exercícios de intensidade leve ou moderada, e principalmente naqueles de duração prolongada. A utilização dos AG pelos músculos esqueléticos depende de passos importantes como a mobilização, transporte via corrente sangüínea, passagem pelas membranas plasmática e mitocôndrial, β-oxidação e, finalmente, a oxidação no ciclo de Krebs e atividade da cadeia respiratória. O exercício agudo e o treinamento induzem adaptações que possibilitam maior aproveitamento dos AG como fonte de energia, ao mesmo tempo em que o glicogênio muscular é preservado. Contudo, as tentativas de manipulação da dieta e suplementação com agentes ativos para aumentar a mobilização e utilização dos AG durante o exercício não apresentam resultados conclusivos. Nesse trabalho, a hipótese de que o ciclo de Krebs é o fator limitante da utilização de ácidos graxos pelo tecido muscular no exercício prolongado é apresentada. ABSTRACTThe Krebs Cycle as Limiting Factor for Fatty Acids Utilization During Aerobic Exercise. Fatty acids are important fuels for muscle during moderate and prolonged exercise. The utilization of fatty acids by skeletal muscle depends on important key steps such as lipolysis in the adipose tissue, plasma fatty acids transport, and passage through plasma and mitochondrial membranes, β-oxidation, and finally oxidation through the Krebs cycle and respiratory chain activity. Acute exercise and exercise training induce adaptations that lead to an increase in fatty acid oxidation. As a result muscle glycogen is preserved. Nevertheless, diet manipulation and supplementation with lipolytic agents that raise fatty acids mobilization and oxidation during exercise failed to show beneficial results on exercise performance. The hypothesis that Krebs cycle is a limiting factor for fatty acid oxidation by the skeletal muscle during prolonged exercise is presented herein.

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“…However, the effect of training on the amount and proportion of fat oxidized during exercise of the same relative intensity is controversial. While longitudinal studies have supported the notion that training has no significant effect on fat oxidation during exercise, 3,21,22 cross-sectional studies have demonstrated a higher fat oxidation rate in trained subjects than in untrained individuals. 23,24 In addition, the increased proportion of fat oxidized during exercise at the same relative intensity is in contrast with the data presented by Achten and Jeukendrup.…”

Section: Discussionmentioning

confidence: 99%

“…The pattern of substrate utilization (fat vs glucose) during physical activities depends on the interaction between exercise intensity and exercising-induced physiological adaptations such as muscular biochemical adjustments that increase the muscle fat oxidative capacity. 1,2 Although controversial, 3 high muscle fat oxidative capacity has been suggested to enhance fat oxidation during exercises at moderate intensity, 4 with significant consequences on daily fat oxidation. 4,5 Therefore, the optimization of muscle fat oxidative capacity by means of adequate physical activities may be beneficial for the regulation of fat balance, and ultimately of body fat mass.…”

Section: Introductionmentioning

confidence: 99%

Behavioral and physiological regulation of body fatness: a cross-sectional study in elderly men

Rimbert¹,

Montaurier²,

Boccadoro³

et al. 2005

Int J Obes

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Objective: To identify the characteristics of physical activity that are the most correlated to total and truncal fatness and to physiological parameters involved in fat oxidation in elderly men. Design: Cross-sectional study. Subjects: A total of 25 healthy elderly men selected with a wide range of physical activity behavior (65.973.4 years). Measurements: Total and truncal fat masses (by dual-energy X-ray absorptiometry), time spent and energy expended (EE day ) at specific activity intensities (o40, 40-60, 460% VO 2max ) during 1 week in free living conditions (using heart rate recording and individual calibrated equations), sport-exercising volume (V sport , using Baecke questionnaire), maximal oxygen uptake (VO 2max ), muscle fat oxidative capacity (OX FA , using muscle biopsy), lipid oxidation and respiratory exchange ratio during exercise at 50% VO 2max (using indirect calorimetry). Results: V sport was the main determinant of total and truncal fatness, VO 2max and OX FA (r ¼ À0.69, Po0.0001; r ¼ À0.80, Po0.0001; r ¼ 0.70, Po0.0001; r ¼ 0.66, Po0.001, respectively). Among physical activity parameters measured over a week, total EE day was the main determinant of total fat mass. Furthermore, EE day at % VO 2max 460 was closely correlated to truncal fat mass, VO 2max and OX FA (r ¼ À0.58, P40.01; r ¼ 0.55, Po0.01; r ¼ 0.49, Po0.05, respectively). Finally, VO 2max and OX FA were positively correlated to absolute fat oxidation and to the contribution of fat to energy production during moderate exercise. Conclusion: Sport-exercising volume is the main factor regulating total and truncal fat masses and physiological parameters involved in fat oxidation. With regard to the characteristics of physical activity, overall energy expended during the alert period plays a major role in the regulation of total body fatness. In addition, vigorous exercises may be beneficial for the regulation of abdominal fat depot partly through the stimulation of muscle fat oxidation during the effort.

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Endurance training increases fatty acid turnover, but not fat oxidation, in young men

Cited by 104 publications

References 27 publications

Effect of exercise training at different intensities on fat metabolism of obese men

Effect of exercise training at different intensities on fat metabolism of obese men

Ciclo de Krebs como fator limitante na utilização de ácidos graxos durante o exercício aeróbico

Behavioral and physiological regulation of body fatness: a cross-sectional study in elderly men

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