Sex differences in phase angle of entrainment and melatonin amplitude in humans.

摘要: Studies of sex differences in the timing human circadian rhythms have reported conflicting results. This may be because studies conducted to date not controlled for masking effects rest-activity cycle on being assessed. In present analysis data collected under conditions, we examined while minimizing from behavioral and environmental factors using a constant routine (CR) protocol. All participants (28 women 28 men paired by habitual wake time; age range 18-30) maintained regular self-selected sleep-wake schedule at home prior study. After three baseline days laboratory, began CR. Women were found significantly higher melatonin amplitude lower temperature than men. While sleep was same between two groups, core body pineal secretion earlier relative time as compared Sleep therefore occurred later biological men, despite clock time. Given that propensity structure vary with phase are impacted circulating melatonin, these findings important implications understanding duration, diurnal preference, prevalence disorders such insomnia.