caa a22 4500 388062908 CHVBK 20180307125126.0 cr unu---uuuuu 161130e199802 xx s 000 0 eng 10.1079/BJN19980022 doi S0007114598000233 pii (NATIONALLICENCE)cambridge-10.1079/BJN19980022 Utilization of lipids during exercise in human subjects: metabolic and dietary constraints [Elektronische Daten] During endurance exercise, skeletal muscle relies mainly on both carbohydrate (CHO) and fat oxidation to cover energy needs. Numerous scientific studies have shown that increasing the exercise intensity leads to a progressive utilization of CHO. The latter will induce a state of glycogen depletion which is generally recognized as being a limiting factor for the continuation of strenuous exercise. Different dietary interventions have been proposed to overcome this limitation. A high-CHO diet during periods of intense training and competition, as well as CHO intake during exercise, are known to maintain a high rate of CHO oxidation and to delay fatigue. However, it has been recognized also that enhancing fatty acid (FA) oxidation during exercise induces a reduced rate of glycogen degradation, resulting in an improved endurance capacity. This is most strikingly observed as a result of frequent endurance exercise which improves a number of factors known to govern the FA flux and the oxidative capacity of skeletal muscle. Such factors are: (1) blood flow and capillarization; (2) lipolysis of triacylglycerol (TAG) in adipose tissue and circulating TAG and transport of FA from blood plasma to the sarcoplasm; (3) availability and rate of hydrolysis of intramuscular TAG; (4) activation of the FA and transport across the mitochondrial membrane; (5) the activity of enzymes in the oxidative pathway; (6) hormonal adaptations, i.e. sensitivity to catecholamines and insulin. The observation that the plasma FA concentration is an important factor in determining the rate of FA oxidation, and that some dietary factors may influence the rate of FA supply to muscle as well as to the mitochondria, has led to a number of dietary interventions with the ultimate goal to enhance FA oxidation and endurance performance. It appears that experimental data are not equivocal that dietary interventions, such as a high-fat diet, medium-chain TAG-fat emulsions and caffeine intake during exercise, as well as L-carnitine supplementation, do significantly enhance FA oxidation during exercise. So far, only regular endurance exercise can be classified as successful in achieving adaptations which enhance FA mobilization and oxidation. Copyright © The Nutrition Society 1998 Fat intake nationallicence Exercise nationallicence Medium-chain triacylglycerols nationallicence Caffeine nationallicence L-carnitine nationallicence Brouns Fred Novartis Nutrition Research Unit, PO Box 1350, NL-6201 BJ Maastricht and Department of Human Biology, Nutrition Toxicology and Environment Research Institute, Maastricht, The Netherlands van der Vusse Ger J. Department of Physiology, Cardiovascular Research Institute, Maastricht, Maastricht University, Maastricht, The Netherlands British Journal of Nutrition Cambridge University Press 79/2(1998-02), 117-128 0007-1145 79:2<117 1998 79 BJN https://doi.org/10.1079/BJN19980022 text/html Onlinezugriff via DOI 1 review-article jats NATIONALLICENCE 856 40 https://doi.org/10.1079/BJN19980022 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Brouns Fred Novartis Nutrition Research Unit, PO Box 1350, NL-6201 BJ Maastricht and Department of Human Biology, Nutrition Toxicology and Environment Research Institute, Maastricht, The Netherlands NATIONALLICENCE 700 1- van der Vusse Ger J. Department of Physiology, Cardiovascular Research Institute, Maastricht, Maastricht University, Maastricht, The Netherlands NATIONALLICENCE 773 0- British Journal of Nutrition Cambridge University Press 79/2(1998-02), 117-128 0007-1145 79:2<117 1998 79 BJN CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge