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Published on: March 2, 2011
Effects of acutely displaced sleep on testosterone
John Axelsson1, Michael Ingre, Torbjörn Akerstedt
1National Institute for Psychosocial Medicine, 171 77 Stockholm, Sweden. john.axelsson@ipm.ki.se
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.
