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J Clin Endocrinol Metab. 2005 Aug;90(8):4530-5. Epub 2005 May 24.

Effects of acutely displaced sleep on testosterone.

Author information

1
National Institute for Psychosocial Medicine, 171 77 Stockholm, Sweden. john.axelsson@ipm.ki.se

Abstract

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.

PMID:
15914523
DOI:
10.1210/jc.2005-0520
[Indexed for MEDLINE]

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