Doctors say it may not ruin your life but it can make your life miserable,
For years now, Allan Rechtschaffen, a psychology professor emeritus at the University of Chicago, has been watching what happens when he totally deprives rats of sleep.
He takes a plastic disc with a divider in the middle and puts one rat on each side. Both rats get plenty of food, and one rat — the lucky one — also gets to sleep whenever it wants.
But every time the other rat dozes off, the disc starts to spin slowly, forcing both rats to jump up and walk forward to keep from falling into a shallow pool of water.
The result? After two or three weeks of total sleep deprivation — probably the equivalent of 8 to 12 weeks for humans — the sleepless rats all die.
During their downward spiral, their body temperature goes up, they develop skin lesions and food intake doubles. They show no changes in immune function.
“We don’t know what the rats die of,” says Rechtschaffen, but “sleep seems to be almost as important for an organism as food.”
Intuitively, that seems obvious. And researchers have documented some very real consequences of sleep loss, which affects not only America’s 30 to 60 million chronic insomniacs but millions of others who are just too busy to sleep or have a medical problem like sleep apnea or restless leg syndrome.
Sleep apnea, which affects at least 2 percent of women and 4 percent of men and can trigger potentially serious cardiovascular problems, causes a person to wake up repeatedly to breathe. Restless leg syndrome and involuntary jerking of the legs during sleep can also make it hard to fall and stay asleep.
Yet the surprising thing about all this research is that while more than 1,000 studies show that a bad night’s sleep — or a string of them — can lead to decreased intellectual function, mood and performance, there’s little evidence so far that sleep loss has direct health consequences.
Except, of course, if you count the 1,500 deaths and 76,000 injuries a year from driver fatigue, accidents that happen when the brain is vulnerable to “intrusions of microsleep episodes,” says Dr. Charles Czeisler, chief of circadian and sleep disorders medicine at Brigham and Women’s Hospital.
Still, overall there is “no solid evidence that sleep loss leads to long-term medical problems,” says Gregg Jacobs, an insomnia specialist at Beth Israel Deaconess Medical Center.
It does cause “psychological suffering,” says psychiatrist William C. Dement, director of the Stanford Sleep Research Center and Sleep Disorders Clinic. “But we can’t say, yes, if you don’t treat your insomnia you are going to die.”
To be sure, insomniacs are “more likely to report poor health,” notes Cynthia Dorsey, director of McLean Hospital’s sleep disorders center, but it’s not clear which comes first.
Twenty years ago, researchers found that people who slept more than nine hours or less than six a night had a higher death rate than those whose sleep was closer to the seven or eight hours that most people need. But this was a correlation, not documented cause and effect.
Recently, there has been new evidence — about a dozen studies — suggesting that immune function may change with sleep loss, but whether this translates into a health risk is also unknown.
Several years ago, Dr. Michael Irwin , a professor of psychiatry at the University of California at San Diego, published a study of 23 middle-aged male volunteers who were awakened at 3 a.m., making them miss about four hours’ sleep.
Irwin found that this modest sleep loss was correlated with a a drop in the activity of natural killer cells, a type of immune cell. But this bounced back fully after a good night’s sleep.
In another study this year, Irwin deprived 42 middle-aged men of sleep in the early part of the night and found decreases in several immune measures, including a substance called Il-2. It was not clear when these measures began to bounce back.
But other studies — and there are still too few for a definitive conclusions — suggest a different picture.
In fact, some measurements of immune function actually go up with sleep loss, says David Dinges , director of the experimental psychiatry unit at the University of Pennsylvania School of Medicine, a researcher who says he has “sleep-deprived more people than anyone else.”
In a 1994 study of 20 adults deprived of sleep for 64 hours, Dinges found an increase in white blood cells and natural killer cell activity, a measure of immune response.
At least in the sleep lab, he says, where researchers go to great pains to keep people in a good mood, sleep deprivation seems to be linked to “an increase in immunological defense,” though the overall picture of immune effects is far from clear.
What is clear, researchers agree, is that sleepless people are not happy campers — or as good thinkers as usual.
“Sleep deprivation has a clear impact on physical performance, cognitive performance and mood,” says Dr. David White, director of the sleep disorders program at Brigham and Women’s and past president of the American Sleep Disorders Association, a professional organization.
But lousy mood can be the cause as well as the effect of lousy sleep. “Nobody knows if depression causes insomnia or vice versa — it’s very circular,” says Dinges.
Anxiety, too, can be part of a vicious circle because “secondary anxiety” can leave people “freaked” about their loss of sleep, says Dr. John Winkelman, associate director of the sleep disorders service at the Brigham.
Making mood worse after a bad night, or several, is the all-too-keen awareness that you may be having more trouble than usual remembering things or processing information, although motivation — such as trying to keep your job — may offset this.
Still, there’s no question that if you have a bunch of bad nights in a row, you build up a significant “sleep debt,” which means working memory may fail, reaction time slows and it becomes harder to pay attention.
Yet this is the devil with which growing numbers of us live — whether we’re insomniacs or just don’t take the time to rest. As a nation, we’re getting 20 percent less sleep than our forebears did a century ago, according to the National Commission on Sleep Disorders Research.
And we’re clearly paying the price. A Gallup survey this year showed that a third of us have significant daytime sleepiness, which can be dangerous as well as unpleasant. A Harris survey, also done this year, found that 70 percent of people acknowledge that their concentration is poor or fair when they’re sleep deprived.
So what should you do if you’re stuck in sleep-loss hell?
For openers, if you’re sleeping only four or five hours a night because you’re too busy or working too hard or socializing too late, put yourself to bed and get more sleep.
If you’ve got a stubborn case of insomnia, tell your doctor. You may have an underlying problem with anxiety or depression; treating these problems can lead to greatly improved sleep.
That goes for sleep apnea, too. Many people deny they have trouble breathing during sleep for the obvious reason that they’re too groggy to remember. But apnea is both serious and treatable, so if your spouse says your snoring is terrible, take it seriously.
Restless leg problems, too, are treatable, usually with medications.
And if you’ve got chronic insomnia?
Despite their bad reputation, sleeping pills may be an answer for some people. A relatively new short-acting one called Ambien appears to cause less dependence than the older, longer-acting benzodiazepines in vogue 10 years ago.
Many people also swear by nonprescription potions like melatonin, which is sold as a dietary supplement, although the scientific jury on that is still out.
But the best long-term solution for many people is to change behavior and attitude, which means sticking to a regular sleep-wake schedule and trying not to worry about sleep loss.
“The main problem with insomnia is people worry about their sleep,” says Peter Hauri, author of the bestseller, “No More Sleepless Nights.” If you worry that sleep loss will wreck your health, “you’ll try even harder to sleep and sleep even less.”
So there’s another tidbit to remember as you toss and turn.
“The most astonishing thing,” says Dinges, is that one or two good nights’ sleep “has a marked effect in reversing nearly all of the physiological and brain and immune function changes induced by sleep deprivation.”
SIDEBAR:
For a better night’s sleep.
If you’re struggling with sleep, tell your doctor. If he or she can’t help, you can probably find a sleep specialist to diagnose and treat your problem at almost any major hospital.
You can also practice habits designed to help your sleep:
- Don’t try too hard to sleep. It can make things worse.
- Don’t drink alcohol or water, or smoke cigarettes near bedtime; don’t drink caffeinated beverages after midafternoon.
- Exercise may help, although the data on this are mixed. But don’t exercise within three hours of bedtime.
- Schedule “worry time” in the early evening, then wind down.
- Restrict time in bed to seven or eight hours. Spending too much time in bed not sleeping can make it harder to sleep.
- Get up at the same time every day, even on weekends.
- Don’t let bed become a negative emotional cue. Stay in bed only when you’re relaxed. If you can’t sleep, get up and do something relaxing until you feel drowsy.