Sleep and Aging: Recent Research

Introduction

It has been shown that as people age, the amount of sleep they receive each night decreases. Quality of sleep decreases with age as well. These trends are attributable to many different causes. Some of which are the result of age-related physiological deterioration, while others are much more easily preventable.

Age-Related Sleep Change

About 40% of elderly people complain about their problems sleeping at night. Studies have shown that older people are disproportionately unhappy about their sleep compared to other age groups. Older people also use more medications to help them fall asleep than other age groups. As a result of these sleep problems, they tend to sleep more in the daytime and their functioning during the day is impaired. Polysomnographic studies have shown that the elderly spend more time in bed than other age groups, but spend less time asleep. They take longer to fall asleep, awaken more frequently during the night and for longer periods of time, and have less efficient sleep. They also spend less time in REM and slow wave sleep during the night than younger people. These problems are primarily age-related and not due to other causes of sleep problems. Sleep disorders, mental and physical problems, and poor sleep hygiene can also lead to sleep problems.

Sleep is also affected by diseases which become more prevalent as age increases, such as dementia. But, it has been shown that if diseases, pain, or life stressors are controlled, then sleep problems decrease dramatically. Sleep disorders, however, can affect sleep quality. Sleep apnea and nocturnal myoclonus (leg movement during sleep) are two sleep disorders that do increase in prevalence with age. Unfortunately, it is unclear as to how much sleep disorders affect sleep quality in the elderly. Improvements in sleep hygiene can dramatically improve the quality of sleep. A person's sleep schedule, amount of napping, diet, bedroom environment, amount of exercise, and use of caffeine, alcohol, and medications can all affect sleep quality.

Sedatives, Melatonin, and Circadian Rhythms

Sedatives are often prescribed for older adults facing sleep problems. Older women are prescribed sedatives almost twice as much as older men. While sedatives work well in helping small or temporary sleep problems, tolerance to the drug develops in many cases. As a result, nightmares and "rebound insomnia" will occur when a person is taken off of the medication. Dependence on these sedatives can impair cognitive functioning, slowed motor movements, and increase the likelihood of falling and injuring oneself.

Melatonin has received a great deal of publicity as to its effectiveness in improving sleep. It is available over the counter now, but it has been shown that melatonin is not nearly as effective as it is thought to be. Melatonin would be beneficial primarily to those who have low levels of melatonin already. People with high levels of melatonin would find the supplementary use of it to be counterproductive and actually impair sleep. Potential side effects have not been explored and the amount of melatonin available for a person at this time is far short of the optimum amount needed to dramatically improve sleep. Melatonin works with the body's circadian rhythms to regulate the timing and quality of sleep. Evidence has emerged that shows that "changes in the physiological systems that generate and regulate circadian rhythms" with age may be the cause of sleep problems.

Circadian Pacemaker

The circadian pacemaker "regulates the timing of sleep within the 24 h day." It has been shown that age-related changes in the circadian pacemaker do lead to sleep disturbances in older adults, but previous studies were flawed. One study aimed to determine if there are any age-related changes in the pacemaker by using participants who have had no prior sleep problems.

Twenty-seven young men (ages 18-31) and twenty-one older adults (ages 65-85; 11 men and 10 women) were used in the study. All were in good health and without sleep problems. Young women were excluded due to the "effects of gonadal steroids on the core temperature rhythm." No subjects had traveled across any time zones within 3 months or worked a night-shift job within 3 years. The participants were kept awake for 40 hours while their environments were controlled. Their core temperature was monitored throughout the study as well.

It was shown that the young men had the highest core temperature and that older women had a slightly higher temperature than the older men. Bedtimes and waketimes were earlier in the older group and their "daily alertness peak" arrived earlier as well. This is strong evidence showing that the output of the circadian pacemaker decreases with age. This decrease is a major cause in sleep problems in older adults and is most likely the result of deterioration of the hypothalmic nuclei with age. The hypothalmic nuclei are responsible for driving circadian rhythms.

Possible Treatments

Since there are so many possible causes to sleep disturbances in the elderly, there must also be a lot of treatments. For example, urinary frequency may contribute to sleep disturbances, and therefore, limiting fluid intake would be necessary. Sometimes certain medications can impair sleep quality. Lowering doses or replacing the drug with another would solve this problem. Sleep problems can also be the result of certain psychological disorders such as depression, anxiety disorder, or obsessive compulsive disorder. Treatments for these disorders would then be needed in order to improve sleep quality. If poor sleep hygiene is the cause, then those bad habits which contribute to impaired sleep quality would need to be replaced or extinguished. If the problem is more serious, such as sleep apnea (impaired breathing during sleep), then there are treatments for that as well. In all cases, though, the person must seek the help of his/her primary physician. Most sleep disturbances or disorders can be treated, as long as you contact your doctor.

Conclusion

Increased sleep disturbances in the elderly is well documented. Many treatments also exist to help the elderly sleep better. Unfortunately, in order for the treatment to be applied, the cause of the sleep problems must be identified. While it seems apparent that we all have a tendency to have impaired sleep quality as we age due to universal physiological reasons, such as the circadian pacemaker, many other causes exist which are much more specific to each person. In order for the causes to be identified and treated, professional help must be sought out.

References

Czeisler, Charles A. (1992). Association of sleep-wake habits in older people with changes in output of circadian pacemaker. The Lancet, 340, 933-936.

Mendelson, Wallace. (1997). A 96-year-old woman with insomnia. The Journal of the American Medical Association, 277n12, 990-996.

Prinz, Patricia N. (1990). Geriatrics: Sleep disorders and aging. The New England Journal of Medicine, 323n8, 520-526.

Vitiello, Michael V. (1997). Sleep disorders and aging: Understanding the causes. Journals of Gerontology--Series A: Biological Sciences & Medical Sciences, 52An4, 189-191.

Contributed by Kent Miller, October 2, 1997.
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