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7 Shocking Facts About Sleep

  • Sarah Kehoe

    1. Flu-Z's

    If you're sleep-deprived before getting your flu shot, it can take three to four weeks for the vaccine to kick in. Those who don't get appropriate rest have a weaker immune system, which hinders the vaccination's effectiveness.

    Source: University of Chicago and Ohio State University study

  • Laura Doss

    2. Take This to Heart

    Poor sleep is more dangerous to women than to men. Women experience higher risks of cardiovascular problems when they don't get enough rest and they're also more susceptible to psychological distress, depression, and anger.

    Source: Duke Medicine

  • Laura Doss

    3. Big-C Shifts

    There's a link between those who work night shifts and breast cancer; researchers say they think it's because melatonin is suppressed, which is necessary for protection against some cancers. "Shift work that involves circadian disruption" is officially listed as a probable carcinogen.

    Source: World Health Organization's International Agency for Research on Cancer

  • istockphoto

    4. Gasp! Wait... What?

    Not only does lack of sleep hurt your ability to learn, but there's also a link between sleep-disordered breathing (i.e., sleep apnea) and dementia in women. Mental impairment is consistently associated with hypoxia, which is when the brain gets less oxygen due to breathing disruptions.

    Source: Journal of the American Medical Association

  • istockphoto

    5. Rise and Grind

    Auto accidents increase by 17 percent on the Monday after Daylight Saving Time occurs, which is when people "lose" an hour of sleep. Heart attacks increase by approximately 5 percent.

    Source: University of British Columbia and New England Journal of Medicine

  • istockphoto

    6. Pillow Balk

    For couples who sleep together (a whopping 23 percent don't), one partner typically loses about 49 minutes of sleep every night, due to disruptive behaviors. These could include anything from a companion's tossing and turning, the TV being on, the room's temperature being too hot or cold, and more.

    Source: National Sleep Foundation

  • Susan Pittard

    7. Sleep Sweep

    It's important to take responsibility for your sleep health, because the truth is that your general physician may not know that much about sleep. Doctors today typically receive less than a semester's worth of sleep education, and sleep medicine wasn't recognized as an individual practice until 1995. One doctor recently told a FITNESS editor, "I only get so much time to see each patient. As much as I'd like to talk to them about their personal issues, I don't have time to ask how they're sleeping."

    Source: American Medical Association...and an anonymous doctor based in Los Angeles

    Originally published on, October 2011.