Parents can attest to the virtues of a good night's sleep, and with frequent awakenings by small children, these nights are in often in short supply. In fact most people are familiar with the effects of a less than restful night. But what is it about sleep that we need? And how much sleep is enough to restore us?
Though it is still not entirely clear why we sleep, it is clear what happens if we don't. Below, Dr. Rafael Pelayo of Stanford University's Sleep Disorder Clinic talks about sleep requirements, the dangers of sleep deprivation, and false assumptions that people make about the meaning of sleeplessness.
How much sleep do people need?
The ballpark figure is eight hours. But the more important question is: Do you wake up feeling refreshed and full of energy or not? There are some people who only seem to feel refreshed after 61/2 hours of sleep, where others need 9 hours.
What are the benefits of sleep?
Nobody really knows why we sleep. The simplest answer is that sleep restores our body, restores our minds, and helps us think better. There are theories that nighttime dreams help us to consolidate our memories. There are other theories about how sleep electrically recharges the brain and restores brain chemicals to its proper levels.
What is the difference between being sleepy and tired?
If I got up and did a hundred jumping jacks, I might feel tired, but I wouldn't feel sleepy. Sleepiness is a feeling of lack of sleep, obviously, and tiredness is a feeling of physical fatigue.
Does everyone have the same sleep requirements?
No. It varies, not only in the amount of sleep, but the timing of sleep. There are true night owls and true morning larks. Some people are genetically inclined to be morning people and others seem to be set up to be night people. There are short sleepers and long sleepers. Some require more sleep than average and some seem to require less than average to feel refreshed and energized.
Do we need more or less sleep as we age?
You should never need more sleep as you age. If, in your youth, you thought you performed well at seven hours of sleep, you should not need 7 1/2 or eight as an older adult. If you find that your sleep demand increases, then you are probably compensating for a decreased quality of sleep. And when we think about sleep, it's important to think not just about the amount of sleep, but the quality as well.
What happens in the body when we don't get enough sleep?
The first thing that happens if you don't get enough sleep is you have problems with your memory and concentration. Usually there are word-finding difficulties-you can't find the words you are thinking of. People also get irritable with lack of sleep.
At its extreme, sleep deprivation can lead to death-for example, lab rats die of infection if they are sleep deprived. So we know that sleep is somehow related to the immune system. It restores the body physically.
Are there biochemical changes that result from sleep deprivation?
Yes. There are neurotransmitters that are altered. And certain hormones-growth hormone for instance, which is involved in our metabolism-is secreted in our sleep; it peaks in our sleep. So one of the signs of poor sleep in children, for instance, is stunted growth.
What is the economic impact of sleep deprivation in the United States?
We think that the cost to society of sleep disorders is approximately $90 billion. That includes lost productivity, absenteeism at work, people getting into accidents, the cost of medications for sleeping pills or for stimulants-all these things cost money.
How does poor quality of sleep affect quality of life?
The true impact of unsatisfactory sleep on the quality of life of individuals is probably impossible to calculate. It's often said, "If mama ain't happy, nobody's happy." If somebody in the family does not sleep, it affects the entire family. Children tiptoe around the house not to disturb the mother; she may feel bad because she doesn't want to disturb the family; the family won't make plans for the next day until they see how their non-sleeping member feels. And the more they try to make the problem better, the worse it gets, the more frustration the family feels.
And I've met many couples in my work; I've never met two insomniacs married to one another. There are higher divorce rates in people with sleep problems. So it impacts the entire family.
Often people who are sleep deprived don't feel they're performing their jobs adequately. Their concentration and memory is impaired, and they make mistakes. They get irritable.
Are there stigmas attached to people who have difficulty sleeping?
The stigma is that if you can't sleep, you must be depressed, and that's simply not true. And certainly, a lot of people with depression have insomnia. But most people with insomnia are not depressed. But unfortunately, if a 30-year-old woman goes to a doctor's office and says that she can't sleep, she's more likely to walk out with a prescription for an antidepressant than a referral for a sleep evaluation with a specialist, and that's simply not fair.
People also often feel that their sleep issues are a problem that's in their head and they should be able to figure it out on their own. People don't realize that they can be helped and that there are physicians who specialize in sleep problems. Often people go to their primary care physician, do not receive a satisfactory answer and then just move on to something else, for example, an over-the-counter remedy or alcohol.
What they should really do is if they're not satisfied with the doctor's recommendations, they should ask to speak to a specialist. Sleep conditions do improve and people should not be embarrassed about this problem. Virtually all the patients with insomnia will improve when their problem is addressed correctly.