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Women's Health Research Institute Putting Women's Health Research First
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November 2012
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Dear Friends,
Until recently, sleep was often considered just a block of time when you gave your brain and body some rest. With the rise in interest in sleep research, we now know that sleep has distinct stages that cycle throughout the night in predictable patterns. Each of these stages impact our body in different ways and all are important to stay healthy and function at our best. Sleep patterns vary from person to person and change across the lifespan. Hormones also play a significant role in sleep and researchers are finally looking at sex differences in sleep disorders.
This edition of our e-newsletter examines some of the key elements that influence sleep in women. We also encourage you to read the Institute Happenings and consider celebrating our Fifth Anniversary with us on November 13!
Regards,
Institute Staff
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What's New in Sleep Research?
How prevalent are sleep disorders?
An estimated 40 million Americans report having a sleep disorder and women are twice as likely as men to have difficulty falling asleep or staying asleep. Women in our Illinois Women's Health Registry are no exception. While 83% of women on the Registry report that they have never had a sleep disorder, 8% report restless leg syndrome, 6% report sleep apnea, and 3% report other, unspecified sleep disorders.
Most of the sleep data on women is related to pregnancy. Eight out of 10 women experience sleep problems during pregnancy, more than at any other time in their lives. However, we now know that males and females have different sleep patterns across the lifespan. Dr. Hrayr Attarian of the new Women's Neurology Clinic at Northwestern, noted in his October 2nd lecture on "The Influence of Hormones on Sleep" at the Women's Health Research Institute monthly forum that sex differences in sleep patterns start in infancy (9-10 month of age), with females sleeping more than males, on average. In adulthood, females still require more sleep than males, but usually get less sleep (Walsleben, 2011).
How do hormones influence sleep?
The key hormones involved in women's sleep include cortisol, estrogen, FSH/LH, melatonin, progesterone, prolactin and TSH. According to Dr. Attarian, the flow of these hormones is regulated by the hypothalamus in the brain and sleep impacts this regulation. For example, blood levels of the stress hormone cortisol, which promotes wakefulness, increase during the end of a complete sleep cycle. Low estrogen levels after menopause are associated with poor sleep patterns that are often improved with estrogen replacement therapy.
Also important to sleep is the circadian system, the physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in our environment. To read more about the physiological factors involved in sleeping visit the Sleep Foundation site.
What are the most common sleep problems in women?
According to Walsleben (2011), many sleep problems, and problems that may be derived from sleep disturbances, are more common in women than men, including:
- Insomnia: not being able to fall asleep, waking up several times a night, waking too early and not being able to get back to sleep
- Restless-leg syndrome: discomfort, creeping, tingling, burning, cramping in legs during the night that interrupts sleep
- Sleep-related headaches
- Fibromyalgia: syndrome in which a person has long-term, body-wide pain and tenderness in the joints, muscles, tendons, and other soft tissues
- Sleep-related eating disorders
- Nightmares
- Familial sleep paralysis
Research Directions in Sleep
Kristen Knutson, PhD, an assistant professor at the University of Chicago, recently published a review of the literature on sleep and obesity. She reported, "There is substantial evidence suggesting that inadequate sleep may increase the risk of obesity, and, importantly, the cardiometabolic diseases associated with obesity, including diabetes and hypertension" (2012). Inadequate sleep can alter the hormones that control hunger; "for example, after a short sleep, gherlin, which stimulates appetite, is higher, and leptin, which signals satiety or fullness, is lower," Knutson recently stated in a Chicago Tribune article on the topic (The Chicago Tribune, Section 1, 09-30-2012)
Studies have also shown that female shift workers, such as nurses and flight attendants, may have increased infertility (Summa, Vitaterna, & Turek, 2012), but these reproductive problems have been poorly studied. New research conducted by Fred W. Turek, PhD at Northwestern University demonstrates that disrupting the "internal clock" of female mice has a significantly negative impact on pregnancy. While control mice had full-term pregnancies 90% of the time, the phase-delay group (light/dark cycles shifted back) had a 50% success rate, and the phase-advanced group (light/dark cycles shifted forward) only a 22% success rate (Summa, Vitaterna, & Turek, 2012). While researchers still don't know exactly how or why this occurs, these findings may have important implications for women who have recurring sleep disturbances and are trying to become pregnant.
Knutson, K.L. (2012). Does inadequate sleep play a role in vulnerability to obesity? American Journal of Human Biology, 24(3): 361-371. http://onlinelibrary.wiley.com/doi/10.1002/ajhb.22219/full
Summa, K.C., Vitaterna, M.H., & Turek, F.W. (2012). Environmental perturbation of the circadian clock disrupts pregnancy in the mouse. PLoS ONE 7(5): e37668.
Walsleben, J.A. (2011). Women and sleep. Handbook of Clinical Neurology (98): 639-651 (available online at http://dx.doi.org/10.1016/B978-0-444-52006-7.00040-X)
Resources:
Your Guide to Healthy Sleep www.nhibi.nih.gov/health/public/sleep/index.htm
http://www.sleepfoundation.org/sites/default/files/SleepWakeCycle.pdf
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HEALTH TIP
To get a better night's sleep:
 Avoid caffeine and nicotine.- Don't exercise too late in the day.
- Avoid large meals and alcohol late at night.
- Don't nap after 3 pm.
- Relax before bed (e.g., hot bath, light reading)
- Stick to a sleep schedule-go to bed and wake at the same time each day.
- Get rid of distractions in bedroom: bright lights, TV/computer screen, noise
- See a doctor if you continue to have sleep issues.
Source: HHS National Heart, Heart, Lung Institute
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INSTITUTE HAPPENINGS 
In conjunction with our Fifth Year anniversary, we are getting a makeover! The Institute for Women's Health Research has changed its name to the Women's Health Research Institute---putting women first!
We have also updated our website and will host a celebration in conjunction with our monthly forum on November 13th.
This is the 30th edition of our monthly e-newsletter, just one example of the many educational tools we develop at the Institute and make available to the public. Please consider supporting our mission to improve women's health by attending our anniversary event or by making a donation. Every little bit helps!
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