In the Nurses’ Health Study, which followed 71,617 women for a decade, those who slept eight hours a night had the lowest risk of developing heart disease. But in another study that followed 84,794 nurses for up to 24 years, those who slept nine hours or more a night were twice as likely to develop Parkinson’s disease as those who slept an average of six hours or less.
Still, many more people, both lay and professional, are more concerned about not getting enough sleep than about too much closed eyes, and with good reason. People who are sleep deprived are more likely to have accidents and fall asleep at inappropriate times, like at a play or concert, or, worst of all, while driving.
Drowsy driving slows down reaction time just like drunk driving. According to the National Highway Traffic Safety Administration, fatigue leads to 100,000 automobile accidents and 1,550 auto fatalities annually in the United States. Several automakers, including Subaru, Audi, Mercedes and Volvo, now offer drowsiness detection systems that monitor a car’s movements, such as lane deviations, and warn drowsy drivers to take a break.
Sleep deprivation has been a factor in some of the greatest environmental disasters of recent decades, including the 1979 Three Mile Island nuclear accident, the 1986 Chernobyl meltdown, and the 1989 Exxon Valdez oil spill in Alaska.
How we sleep can affect what we eat
Although you might expect the opposite, several studies have shown that short sleepers tend to weigh more than those who sleep longer, even though people burn more calories when awake than when they sleep. A study of 990 working adults in rural Iowa found that the less sleep they got during the week, the higher their body mass index tended to be.
A Canadian study of 240 children aged 8 to 17 showed that compensating for short weeknight nights with longer weekend sleeps was unhelpful. Fluctuations in sleep times can affect appetite-regulating hormones in such a way that people eat when they are not hungry and eat past the point of satiety. The Wisconsin Sleep Cohort Study found that short sleepers had low levels of the appetite-suppressing hormone leptin and higher levels of the hormone ghrelin, which signals people to eat more.
Additionally, trying to catch up on lost sleep over the weekend has been associated with eating without hunger or in response to fatigue, and with being overly tempted by the sight or smell of food. I can confirm a general tendency to eat more – particularly snacks of questionable nutritional value – when staying up past a reasonable bedtime.
Promote a good night’s sleep
Experts offer a variety of tips for better sleep. Among them:
Avoid all sources of caffeine in the late afternoon and evening, and avoid a large, heavy meal just before bed.
Practice good sleep hygiene. Go to bed and get up around the same time every day.
Do not use alcohol to relax. Try a warm bath or meditation.
Reading before bed is great, as long as it’s not on a computer or tablet that emits sleep-inhibiting light.
If outside light interferes with sleep, install light-blocking blinds or curtains, or use a sleep mask. If noise is a problem, use earplugs or a white noise device.
Consider cognitive behavioral therapy, which challenges underlying thoughts or behaviors that may be keeping you up at night.