Shift work winds forward the biological clock - study
Because the same part of the mammalian brain which controls our circadian rhythms – the suprachiasmatic nucleus – also handles the menstrual cycle in females, scientists in Japan and the US decided to take a look to see if there was any link between the two.
What they found was messing with the natural light-dark cycle lowered fertility in older female mice, but had no effect on their younger sisters.
The good news however is that by reverting the light-dark cycle back to normal, reproductive function can be restored.
"In modern society, females are exposed to many challenging perturbations in the environment that might play a role in fertility difficulties – we now live with high light levels in the evening, and our sleep cycle is disrupted by shift work or crossing time zones," says study co-author Gene Block of the University of Los Angeles.
"The ability to rescue reproductive function by altering the light schedule in a rodent model suggests that improvements in 'circadian hygiene' – for example, reductions in evening illumination, more regular meal timing, or avoiding rotating shiftwork or schedules that lead to irregular sleep – may all be important remedies for reproductive difficulty."
Dr Block says corresponding studies will need to be done on humans to confirm the same effect on shift-working women.
The research is published in today's issue of journal Cell Reports.