Sleep helps restore and rejuvenate the brain and organ systems -- including the reproductive system. When sleep suffers over the long run, so does our relationship with our spouse, our mood, our immunity, and even our hormone balance. Sleep loss can also lead to fertility-disrupting lifestyle factors like caffeine overuse and weight gain.
Lack of sleep may even lead to menstrual irregularity -- a factor that can delay the time it takes to conceive. When researchers polled women in notoriously sleep-deprived professions -- flight attendants and nurses working the late shift -- half of the women reported irregular menstrual cycles (compared to about 20 percent of the general population). Some stopped ovulating altogether.
Even the light we are exposed to on a day-to-day basis has an influence on ovulation and reproductive hormones -- one that has fascinated (and perplexed) researchers for years. "There is some evidence that before the age of artificial lighting, birth control pills, and working indoors, women all ovulated in sync with the phases of the moon," says Joyce Stahmann, M.P.H., a fertility educator and professional herbalist in Portland, Oregon, who teaches the Natural Fertility Management Program.
Similarly, researchers at the University of California, San Diego, Sleep Lab have successfully been able to alter the length of women's menstrual cycles by exposing women to artificial light around the middle of their cycles, while they slept. It appears that the hormones that trigger ovulation, and even the sperm maturation process, are somehow tied into the body's biological clock, explains Daniel Kripke, M.D., the current director of the Sleep Lab, who oversaw some of this research. Dr. Kripke is a world-famous circadian rhythm expert and a professor of psychiatry at the university.
The calibrated release of sleep-wake hormones such as melatonin and cortisol is triggered, in part, by information given to the brain by its "light meter," the pineal gland. Since the same part of the brain that regulates sleep-wake hormones also stimulates daily pulses of reproductive hormones for men and women, scientists suspect some feedback between these systems. Another concern is the effect that natural light can have on mood. "Lack of sunlight can result in depression, which in turn can suppress fertility," notes Dr. Kripke.
