Humans spend about a third of their lives sleeping—at least the lucky ones do. But many of us have insomnia, which simply means difficulty falling or staying asleep. Estimates vary, but perhaps one-quarter to one-third of all adults—and half of those over 65—regularly suffer from insomnia, and nearly everybody has it at some time. In addition, some people choose to curtail their sleeping hours to squeeze in more time for work or play, while others are forced to do so by circumstances.
According to the National Sleep Foundation, 60 percent of Americans say they get only a few good nights of sleep a week. It’s hard to know exactly how many people have insomnia largely because it varies so much. It can be chronic and defy explanation. It can be transient and go away by itself or when you deal with its cause. Or it can morph from transient to chronic, depending in part on how you deal with it.
You may have trouble falling asleep, staying asleep, or both. You may sleep well on alternate nights, or with the help of a sleeping pill. You may often fall asleep easily but wake very early and not get back to sleep (a pattern often related to anxiety). Whatever the pattern or cause, inadequate sleep can make you feel exhausted all the time, adversely affecting your ability to work, think and drive. And as accumulating research shows, chronic poor sleep can harm your physical and mental health.
Risks of poor sleep
Chronic poor sleep can cause or contribute to many serious health problems. Notably, sleep helps support the immune system; one week of poor sleep can lower resistance to infections and impair wound healing. Studies have also strongly linked poor sleep to increased risk of hypertension, type 2 diabetes, stroke, heart attack, cognitive impairment, depression, anxiety disorders and premature death.
Such associations do not prove cause and effect. Shorter (and longer) sleep can be the result of various health problems and can worsen pre-existing health problems, resulting in a vicious circle. The risks posed by poor sleep are clearest when it is the result of obstructive sleep apnea, a growing problem.
There’s accumulating evidence linking poor sleep to increased calorie intake, weight gain and obesity. One proposed mechanism is that poor sleep affects the appetite hormones ghrelin and leptin. It can also impair glucose tolerance and increase insulin resistance, which can lead to weight gain. Sleep deprivation tends to decrease people’s motivation to diet and exercise. Having extra waking hours also means more time to eat. And in another vicious circle, obesity can in turn worsen sleep, particularly if it leads to sleep apnea.
Poor sleep can have many adverse effects on the brain and central nervous system. Even one night with only a few hours of sleep can impair concentration, coordination, productivity, judgment, and emotional stability. And what affects the mind often affects the body, of course. It’s no coincidence that poor sleep and impaired memory frequently accompany aging. A recent study from UC Berkeley, published in Nature Neuroscience, linked certain structural changes in the brains of people in their 70s with both reduced deep sleep and cognitive decline. It’s a double whammy—brain deterioration impairs memory, and the disrupted sleep only worsens matters. Not exactly good news for older people, but it suggests that finding ways to help them sleep better may help prevent some cognitive losses.
Sleep problems: What your doctor can do
If you’ve been sleeping poorly for several weeks and taking simple steps for better sleep haven’t helped, talk to a health care provider. Most people never mention their sleep problems. The following conditions are leading disruptors of sleep, and good medical advice can help you deal with them: sleep apnea, chronic pain, illness (such as thyroid disorders), restless legs syndrome, nocturnal leg cramps, an enlarged prostate (leading to frequent trips to the bathroom), severe menopausal hot flashes, shift work, chronic depression or other psychiatric conditions, and taking medications that interfere with sleep. If your problems persist, your health care provider should refer you to a sleep specialist, who will evaluate you and may have you undergo testing at home or at a sleep clinic (see the box. "Checking Into A Sleep Clinic," below). Or you may be referred to a cognitive behavioral therapist.