Our bodies change in many ways as we get older. Sleep is no different. Realizing that changes in sleep are a common part of aging will provide you with a sense of control over sleep. As we age, the amount of sleep we obtain changes, sleep decreases from sixteen to eighteen hours a day in newborns to nearly ten hours for ten-year-olds and to approximately eight hours during the teenage years. We sleep about seven hours a night in middle age and by our seventies sleep time decreases to roughly six and half hours. However, we compensate by obtaining about an hour of additional sleep in the form of daytime naps.
Experiments have been done with volunteers who tried to reduce their sleep from the usual seven and half hours to five and a half hours by decreasing their sleep by thirty minutes every two weeks. Most of the volunteers had little trouble reducing sleep by a half-hour, or even an hour, but they began to notice some difficulty when sleep was reduced by more than this. They were able to awaken on time, and they were able to function at work and in their social life, but they found themselves simply more fatigued. The sleep reduction did not seem to pose a threat to anyone’s health, but they found themselves to be more irritable, more pessimistic, and less fun to be with. For most adults, reduction in the amount of sleep is possible, but fatigued and changes in mood make it undesirable. It is estimated that about half of the adult North American population is already sleep deprived and any further reduction would have marked changes on mood and performance.
The amount you sleep does affect your chances of living longer. There was a study conducted by the American Cancer Society for over a period of six years with one million Americans in San Francisco. Their survival was rated against many lifestyle factors, including sleep patterns. Surprisingly, men who slept four hours a night or less had a mortality rates ten times greater than that of those who slept between seven and eight hours. It seemed that any deviation from usual sleep requirements for adults of six to eight hours was accompanied by a significant increased risk of mortality. In fact, the National Center for Health Service Research in the United States considers adequate sleep one of the six most important factors affecting illness and death rates; the other lifestyle factors include regular exercise, not smoking, limited consumption of alcohol, regular meal schedules, and maintenance of proper weight.