Shift work may pose greater risk to women: study

Source: Safety+Health, April 20, 2016

Women are more likely than men to be affected by the adverse ramifications of shift work, a new study out of England suggests.

Researchers from the University of Surrey’s sleep center placed 16 men and 18 women on 28-hour days to desynchronize them from the brain’s typical 24-hour circadian clock. Participants then performed several tasks every three hours when they were awake.

The sleep cycle simulated the effect that shift work or jetlag may have on workers. Researchers found that the desynchronized circadian clock affected sleepiness, mood and effort, as well as working memory and temporal processing to a smaller degree. ….
Sex differences in the circadian regulation of sleep and waking cognition in humans
Source: Nayantara Santhi, Alpar S. Lazar, Patrick J. McCabe, June C. Lo, John A. Groeger, and Derk-Jan Dijk,Proceedings of the National Academy of Sciences, Early Edition, published ahead of print April 18, 2016

Circadian rhythms affect our physiology and psychology, in health and disease. Most of our knowledge about the human circadian timing system is based on research in men. Some circadian characteristics, such as the intrinsic frequency of the circadian clock and the amplitude of the melatonin rhythm, have been shown to differ between men and women. Whether the circadian regulation of mental functions differs between men and women is unknown. Here we show that circadian rhythmicity in mental functions exhibits sex differences so that the night-time impairment in cognitive performance is greater in women than in men. These findings are significant in view of shift-work–related cognitive deficits and disturbances of mood, which are more prevalent in women.