The Health Hazards of Sleepiness
Sleep Deprivation and Health Problems
The mental toll of skimping on slumber can be serious. A 2002 survey by the National Sleep Foundation found that more than nine out of 10 people said that not getting enough sleep can erode their performance at work and increase the risk of injuries. Nearly two-thirds felt that lack of sleep can muddle their thinking, rendering it more difficult for them to make decisions and listen carefully, and making them more prone to mistakes and to flying off the handle when faced with routine annoyances. Even their mental outlook was dampened: Short sleepers were nearly three times as likely to feel angry as were those who got plenty of shut-eye.
Serious sleep deprivation can also cause uncontrollable sleep attacks -- dozing off for three or four seconds without even feeling the "microsleep" coming on, according to Hans Van Dongen, PhD, a sleep researcher at the Pennsylvania University School of Medicine, in Philadelphia.
"You will wake up almost immediately, which isn't such a problem if you're at home or sitting at your desk," he says. "But if you're behind the wheel, it can be deadly."
Sleep experts feel this is as important to be aware of as not driving drunk, a comparison that a 2000 Australian study bears out. Researchers looked at people who were awake for up to 20 hours straight and found that some scored worse on tests of their reaction time than those with a blood alcohol concentration of 0.1 percent, which is considered legally drunk in every U.S. state. And like drunk drivers, the sleep deprived are a real on-the-road menace. Each year they're responsible for more than 56,000 car crashes, resulting in 40,000 injuries and 1,550 fatalities, according to the National Highway Traffic Safety Administration. Indeed, 12 percent of women admit to having dozed off at the wheel, according to a 2002 National Sleep Foundation survey.
Lack of sleep can be hazardous in other ways, too. It may throw off the body's production of cytokines, immune molecules that help you fight infections, says Dr. Walsleben. And white blood cells called natural killer cells, which attack tumors and viruses, have been found to decrease with sleep deprivation, says Jean K. Matheson, MD, a neurologist and medical director of the Sleep Disorders Center at Beth Israel Deaconess Medical Center, in Boston.
Moreover, a 2003 Harvard study showed that women who slept for five hours or less a night were 45 percent more likely to develop heart disease than women who slept eight hours. One reason too little sleep may tax the heart, doctors believe, is by spiking levels of the stress hormone cortisol, which can elevate blood pressure.
Severe sleep deprivation may even set you up for diabetes and becoming overweight, according to a 1999 University of Chicago study. During the 16-day experiment, 11 healthy young men were in bed eight hours per night at first, then four hours the second week and 12 hours the third week. In the week they were sleep deprived, their sympathetic nervous systems became more active, which prevented their pancreases from producing enough insulin, the hormone the body requires to turn sugar into fuel.
In other words, too little sleep for just one week put the test subjects into a pre-diabetic state. Researchers also noticed that volunteers experienced a 20-percent drop in leptin, a hormone that signals feelings of fullness. This drop can trigger cravings for fat and complex carbs, which may contribute to weight gain.
"We still don't know for sure," says Dr. Walsleben, "but lack of sleep may be a risk factor for insulin resistance, which can lead to diabetes, high blood pressure, and obesity."
The best way to stave off these risks is by making changes to be sure that you get enough shut-eye. "We need to make sleep a priority," says Dr. Hunt. "As we ratchet down from seven to six to five hours of sleep a night, studies consistently show that we're paying a heavy price." And while occasional bouts of insomnia are normal, if sleep problems persist for more than a month, say experts, you should see your doctor for help.
Originally published in Ladies' Home Journal magazine, October 2004.