Effects of exercise on neuroendocrine secretions and glucose regulation at different times of day

André J. Scheen, Orfeu M. Buxton, Maria Jison, Olivier Van Reeth, Rachel Leproult, Mireille Lhermite-Balériux, Eve Van Cauter

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

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 U2 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. Exerciseinduced elevations of temperature were higher in the early morning than at other times of day. The exercise-induced glucose decrease was ~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.

Original languageEnglish (US)
Pages (from-to)E998-E1001
JournalAmerican Journal of Physiology
Volume274
Issue number6 PART 1
StatePublished - 1998

All Science Journal Classification (ASJC) codes

  • Physiology (medical)

Fingerprint Dive into the research topics of 'Effects of exercise on neuroendocrine secretions and glucose regulation at different times of day'. Together they form a unique fingerprint.

Cite this