Physical performance and metabolic changes induced by combined prolonged exercise and different energy intakes in humans.
The purpose of this study was to evaluate the effects on physical performance of three levels of energy intake during a 5-day period of prolonged physical exercise and relative sleep deprivation. A group of 27 male soldiers were randomly assigned to three groups receiving either 1800 kcal.24 h-1 (7560 kJ, LC), 3200 kcal.24 h-1 (13440 kJ, MC) or 4200 kcal.24 h-1 (17,640 kJ, HC). They took part in a 5-day combat course (CC) of heavy and continuous physical activities, with less than 4 h sleep per day. Performance capacity was tested just before and at the end of CC. Maximal oxygen uptake (VO2max) was determined during an exhausting incremental exercise test on a cycle ergometer. Anaerobic performance was measured from the time during which exercise could be maintained at supra maximal loads on a cycle ergometer. After CC, the subjects receiving LC exhibited a 14% decrease in power output at exhaustion in the incremental exercise test [from 325 (SEM 8) to 278 (SEM 9) W, P < 0.001] and a significant decrease in VO2max of 8% [from 3.74 (SEM 0.06) to 3.45 (SEM 0.05) 1.min-1, P < 0.05]. The remaining two experimental groups demonstrated the same mechanical and metabolic performances on days 1 and 5. Anaerobic performance was not influenced by energy intake and the field course. Blood samples were obtained at rest on days 1 and 5. At the end of CC, the data demonstrated a significant decrease in blood glucose concentrated ion (P < 0.01) for LC diet only.(ABSTRACT TRUNCATED AT 250 WORDS)
Guezennec
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Centre d'Etudes et de Recherches de Médecine Aérospatiale, Brétigny sur Orge, France.
Satabin
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Legrand
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Bigard
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D020155:3-Hydroxybutyric Acid; D000693:Anaerobiosis; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D004032:Diet; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism; D005080:Exercise Test; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006801:Humans; D006885:Hydroxybutyrates / Q000097:blood; D007328:Insulin / Q000097:blood; D008297:Male; D008889:Military Personnel; D010101:Oxygen Consumption; D005082:Physical Exertion; D012119:Respiration; D013739:Testosterone / Q000097:blood
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D006885:Hydroxybutyrates; D007328:Insulin; D013739:Testosterone; D020155:3-Hydroxybutyric Acid