Effects of acutely displaced sleep on testosterone.
2005 (English)In: J Clin Endocrinol Metab, ISSN 0021-972X, Vol. 90, no 8, 4530-5 p.Article in journal (Refereed) Published
CONTEXT: It is not yet clear whether the diurnal variation in testosterone is regulated by circadian or homeostatic (sleep) influences. OBJECTIVE: The present study tested whether testosterone is driven by a circadian-independent sleep effect by shifting sleep acutely to daytime in a 24-h sampling regiment. DESIGN, SETTING, AND PARTICIPANTS: In the sleep laboratory, seven healthy young men (age, 22-32 yr) participated in three conditions: habituation (sleep between 2300-0700 h), night sleep (2300-0700 h), and day sleep (0700-1500 h), the latter two in a balanced order. INTERVENTION AND MAIN OUTCOME MEASURE: Serum testosterone was, in all conditions, sampled by hourly blood drawing for 24 h during constant bed rest. RESULTS: Mean testosterone levels increased as a log-linear function of time (hours) across both sleep periods (b = 4.88; P < 0.001), from 15.3 +/- 2.1 to 25.3 +/- 2.2 nmol/liter during night sleep and from 17.3 +/- 2.1 to 26.4 +/- 2.9 nmol/liter during day sleep. Similarly, mean testosterone levels decreased with time (log-linear) awake (b = -1.80; P < 0.001). There was also evidence of a weak circadian component (acrophase ranging between 0651-0924 h) and an increase with time in the laboratory. Moreover, all these effects, except for the increase during sleep, differed significantly between individuals. CONCLUSION: In conclusion, testosterone increased during sleep and fell during waking, whereas circadian effects seemed marginal. Individual differences were pronounced.
Place, publisher, year, edition, pages
2005. Vol. 90, no 8, 4530-5 p.
Adult, Circadian Rhythm/*physiology, Humans, Male, Regression Analysis, Research Support; Non-U.S. Gov't, Sleep/*physiology, Testosterone/*blood, Wakefulness/*physiology
IdentifiersURN: urn:nbn:se:uu:diva-75447PubMedID: 15914523OAI: oai:DiVA.org:uu-75447DiVA: diva2:103358