par Scheen, André Jacques;Buxton, O M;Jison, M;Van Reeth, Olivier 
;Leproult, Rachel ;L'Hermite-Balériaux, Mireille ;Van Cauter, Eve
Référence American journal of physiology: endocrinology and metabolism, 274, 6 Pt 1, page (E1040-E1049)
Publication Publié, 1998-06
;Leproult, Rachel ;L'Hermite-Balériaux, Mireille ;Van Cauter, Eve Référence American journal of physiology: endocrinology and metabolism, 274, 6 Pt 1, page (E1040-E1049)
Publication Publié, 1998-06
Article révisé par les pairs
| Résumé : | To study the effects of time of day on neuroendocrine and metabolic responses to exercise, body temperature, plasma glucose, insulin secretion rates (ISR), and plasma cortisol, growth hormone (GH) and thyrotropin (TSH) were measured in young men, both at bed rest and during a 3-h exercise period (40-60% maximal O2 uptake). Exercise was performed at three times of day characterized by marked differences in cortisol levels, i.e., early morning (n = 5), afternoon (n = 8), and around midnight (n = 9). The subjects were kept awake and fasted, but they received a constant glucose infusion to avoid hypoglycemia. Exercise-induced elevations of temperature were higher in the early morning than at other times of day. The exercise-induced glucose decrease was approximately 50% greater around midnight, when cortisol was minimal and not stimulated by exercise, than in the afternoon or early morning (P < 0.05). This effect of time of day appeared unrelated to decreases in ISR or increases in temperature and GH. Robust TSH increases occurred in all exercise periods and were maximal at night. The results demonstrate the existence of circadian variations in neuroendocrine and metabolic responses to exercise. |
