Scientists are investigating poor quality of sleep as the source for many diseases of aging, including heart disease, cancer and Alzheimer’s. They are working on ways to improve the amount of restful sleep that elderly people get, which researchers believe could promote much healthier lives.
We spend approximately one-third of our lives asleep. In an ideal world, the time spent sleeping is restful, helping to refresh both alertness and memory.
As we age, though, experts say the quality and quantity of sleep becomes poor and fragmented, because the neurons and brain circuits that regulate sleep slowly degrade.
It’s a downhill process they say begins in a person’s 30s. By the time someone is in their 50s, sleep scientists say the average person has lost 50 percent of their capacity for restful sleep, and has trouble falling asleep and staying asleep overnight. From middle age on, sleep specialists say the problems with restful sleep only get worse.
Matthew Walker, a professor of neuroscience and psychology at University of California at Berkeley, is director of the school’s Sleep and Neuroimaging Lab.
He said dream-state or rapid eye movement sleep, known as REM sleep, remains mostly intact as we age. What tends to fall off is non-REM sleep, the deep sleep that leaves people feeling refreshed in the morning.
As people age, their risk of developing heart disease, cancer and Alzheimer’s disease rises. Those conditions are commonly believed to interfere with sleep.
But Walker suggests the problem may be the other way around, "or at least it’s a two-way street I think, and maybe the fact that it’s flowing in more so than one direction. In other words, I think sleep disruption is a novel, underappreciated fact that is contributing to age and dementia as we get older.”
In a meta-analysis, Walker and colleagues reviewed data on 2 million people, in a study reported in the journal Neuron. When they looked at electrical patterns of sleep in sleep-deprived adults, they found slow waves and so-called “sleep spindles,” or bursts of brain activity, which disrupt non-REM sleep.
They also found chemical markers “in spades,” as one researcher put it, in people deprived of restful, non-REM sleep.
Walker said virtually all body systems are affected by a lack of sleep, including the cardiovascular and metabolic systems, which may help explain why people whose sleep is fragmented are more likely to develop heart disease and diabetes.
But Walker said he believes there is a “silver lining” in the findings. Scientists are finding targets to remedy sleep problems, potentially heading off diseases of aging. “We’re trying to develop new sleep therapies to try and generate and assist the aging brain to produce healthy quality of sleep and fight back against the aging and dementia process.”
Walker said novel therapies include stimulating sleep centers in the brain with extremely mild electrical current and magnetism.
In the meantime, he said there are things people can do to improve their quality of sleep. They include exercising, avoiding work on computers and tablet devices before bed that make it harder to fall asleep, and sleeping in a cool room, which also seems to ease people into the very necessary and restful part of their day.