Babies can sleep through a circus. Older kids may fight bedtime. And teens -- good luck getting them out of bed on a weekend.
But what about you -- the grown-up? Your sleep life is still changing -- and not just because time is passing.
How does sleep work in adulthood? Does it change -- for better or worse -- as we age? And why do we feel like we never get enough of it?
An average adult needs between 7.5 and 8 hours of sleep per night. “But many people can function with 6 hours' sleep, and there also some who need 9 hours or more,” says Sudhansu Chokroverty, MD, professor and co-chair of neurology and program director for clinical neurophysiology and sleep medicine at the New Jersey Neuroscience Institute at JFK Medical Center in Edison, N.J.
“The amount of sleep needed to function the next day varies from individual to individual, and is determined genetically and hereditarily," says Chokoroverty, who is also a neuroscience professor at Seton Hall University's School of Health and Medical Sciences.
The biggest, most dramatic change in our deep sleep and satisfaction with sleep takes place as we move from adolescence into young adulthood.
“Most adolescents feel like they sleep terrifically, and if you try to wake them up, you’re not even sure they’re alive,” says Robert Simpson, MD, assistant professor in the University of Utah's division of pulmonary medicine and a sleep medicine specialist. “That’s because they have lots of what we call deep, slow-wave sleep.”
Sleep is broadly split into two big categories: REM (rapid eye movement) sleep, when we’re dreaming, and non-REM sleep. Non-REM sleep moves through several, progressively deeper stages:
- Stage I: a light doze, not very restorative
- Stage II: middle sleep, restorative
- Stage III: slow-wave deep sleep, the most restorative of all
“There’s a fairly precipitous decline in deep slow-wave sleep through the teen years into the early 20s,” Simpson says. “That tends to be replaced with middle sleep, stage II.”
It's Not Just You
You're not just imagining it: As you’ve gotten older, your sleep has probably become less satisfying and less restorative.
To some degree, that may be a part of the natural aging process, but it might also have something to do with your health overall.
“Deterioration in sleep follows general health to a closer degree than it does true chronological age,” Simpson says. “If we track people over time and ask them, ‘How’s your sleep?’ the degree to which it deteriorates or improves over time tends to mirror their overall health.”
Better Health, Better Sleep
As your health improves, your sleep improves -- and vice versa.
The amount of sleep adults get in general has been declining over the past few years.
“If you look at the 1960s and 1970s, people reported average sleep times of 8-8.5 hours a night,” Simpson says. “Today, it’s much more likely to be 7-7.5 hours or less."
Chalk it up to the pace of modern life.
"We lead these frantic lives and we have busy jobs and kids and soccer practice," Simpson says. "Sleep is what tends to get left out, but that has a lot of ramifications for our overall health.”
Why Does Grandpa Nap All Day?
By the time we reach our senior years, we may have more time for sleep -- but once again, we’re not getting it.
There’s a general notion that the elderly need less sleep, but that may not be true, says Simpson, who’s just completed a review of the literature on sleep and aging.
“It turns out that they do get less sleep, but it’s not necessarily because they need less,” he says. “To some extent, their sleep is frustrated by all the issues of aging -- a bad hip, a sore back, heart trouble, a knee that’s out of whack.”
Older people also have a tendency to develop something called advanced sleep-phase syndrome, in which the whole rhythm of their circadian clock is off.
“They go to bed much earlier in the evening and wake up much earlier in the morning,” Simpson says. “The system becomes deregulated and loose, and they kind of unlearn the rhythms of sleep.”
Basically, the elderly revert back to the sleep schedule and patterns of very young children.
“They also wake up many more times during the night than younger adults,” Chokroverty says. “This is why they take naps during the day.”
One way to treat this problem is with bright light therapy in the morning and early evening.
“A good blast of sunlight in the late afternoon and early evening, combined with a little exercise, seems to help people push their clock later and, in turn, wake up later,” Simpson says.
Women, Men, and Sleep
For men, sleep problems tend to get progressively worse with age.
“Primary sleep disorders like insomnia, sleep apnea, circadian rhythm disturbances, and things like restless legs syndrome-they all are worse in the 30s than in the 20s, worse in the 40s than in the 30s, and so on,” Simpson says. “For men, it’s more or less a linear progression.”
But for a woman, sleep patterns tend to be fairly stable until one of two things happen: They get pregnant or they go through menopause.
“Pregnant women see an increase in sleep problems in the first and last trimester. During the first trimester, sleep problems are caused by hormonal changes, and during the last trimester, the baby is larger and creates pressure on the diaphragm, which creates breathing problems,” Chokroverty says. “The baby also puts pressure on the bladder, so a pregnant woman needs to wake up during the night to urinate. Lower back pain and stress and anxiety during the last trimester also cause sleep disturbances.”
About 25% of pregnant women also have restless legs syndrome -- a disorder involving the urge to move the legs to stop unpleasant sensations like prickling or crawling.
And then there’s menopause.
“It truly is cruel,” Simpson says. "Women may have had no problems with sleep their whole lives, except they can’t get any because their children or their job are keeping them up. Then they get the kids raised and the job slows down, and their sleep patterns go absolutely haywire. During menopause, women’s rates of insomnia go through the roof, and their rates of sleep apnea become more or less equivalent to men.”
For these and other sleep disruptions, Simpson advocates trying alternative options before turning to medications.“Instead, start by treating sleep problems with things like breathing exercises, yoga, improving your sleep hygiene by creating a more restful environment in your bedroom, and cognitive and behavioral therapy,” Simpson says.