You already know my husband, Jim, has a remarkable ability to make himself go back to sleep in the middle of the night rather than lie there worrying about things. Clearly he possesses powerful thought-diverting skills, but he also has an innate appreciation of sleep that many people don’t—or that they ignore, as I often do. It’s not that I’m a night owl; it’s that I get backed up during the day and then at 11 P.M. I make a conscious decision to stay up longer to get a few things done that I had wanted to accomplish earlier in the day, such as emails, or looking over a school project, or just some more writing.
And when I do that, Jim invariably walks by me and says something like, “You’ll get more done if you go to bed and do it in the morning.”
Jim tries very hard to get at least 7 hours of sleep a night. It’s not always possible, of course. Sometimes just getting to bed by 11:30 seems like a Herculean effort, given the lingering demands of work, taking care of the house, three kids, and the school projects they seem to “remember” the night before they’re due. Yet the 6 A.M. alarm clock, and the school bell, are immutable. (All of which leads me to suggest that kids are a risk factor for aging, but at least they’ll be there to take care of you when they’ve made you old. Or at least they better!)
Unlike many people, Jim actually thinks about the effect of sleep on his performance. He’s in tune with the way he feels, and he recognizes that when he doesn’t get enough sleep, he simply can’t function at the level he needs to in order to get his work done effectively and still be helpful at night. “Everything’s better when you get a good night’s sleep,” he says (and says, and says). So if he has gone 2 or 3 days getting only 6 or 61⁄2 hours of shut-eye, stay out of his way at 10:30 because come hell or high water, he will be asleep at 11 P.M. Could this be another discipline that’s helping him age so well? Considering the science, the answer is most likely “yes.”
“He recognizes that when he doesn’t get enough sleep, he simply can’t function at the level he needs to in order to get his work done effectively.”
We spend a third of our lives sleeping, and scientists and researchers have been studying sleep for decades, if not hundreds of years, yet we still don’t really know why or even how we do it. But they are beginning to understand the long-term health consequences of not getting enough sleep.
Sleep and aging are closely connected. Older people don’t sleep as well as younger people, and scientists are beginning to find evidence of a vicious cycle: not sleeping well leads to aging, and aging leads to not sleeping well.
People with chronic sleep problems are at much higher risk of a host of diseases and conditions usually considered age-related, including diabetes, dementia, and hypertension. They gain weight more easily and are more susceptible to general illness, less responsive to vaccines, more vulnerable to stress and depression, and tend to have higher blood pressure. Now, perhaps not surprisingly, researchers have linked markers of accelerated cellular aging to poor sleep. Your cells, once again, are listening.
Yet getting too little sleep has become a major problem in this country. About 10 percent of the population suffer from true insomnia, and a quarter reports occasional sleep problems, according to the Centers for Disease Control. Some people suffering from true medical or hormonal conditions that interfere with sleep may find varying degrees of help from behavioral and medical interventions, such as meditation (again) or sleeping pills.
But the real problem seems to be, increasingly, that we just don’t seem to value sleep enough. We power through until late at night, ignoring our body’s sleep signals as we hammer on the computer or otherwise work (or play) until the wee hours. If we sleep a little less, so what? We’re getting it done and getting ahead! Sleep data suggests this is the trend. Thirty years ago, time-use studies conducted by the government showed that the typical American got just over 8 hours of sleep. In 2007, the same study showed Americans get just over 7 hours of sleep a night.
You may see that and think, One hour less sleep. What’s the big deal? But 1 hour is a big deal when you start to get below 7 hours of sleep. And if the average American gets 7 hours, a whole lot of people are getting a lot less than that average.
Immunity Mutiny and More
Although sleep deficits appear to influence and speed up the aging process over time, the impact of sleeping just a little bit less can be immediate.
Remember Carnegie Mellon researcher Sheldon Cohen, who tested for inflammation in stressed individuals by exposing them to the cold virus? Well, he seems to make a habit of exposing subjects to cold viruses: in another study, he used the rhinovirus to see if people who sleep less are more vulnerable to the common cold.
His team tracked the sleep habits of 153 healthy adults age 21 to 55 for 2 weeks and then exposed each of them to the common cold by putting droplets of the virus in their nostrils and quarantined them in a hotel for 5 days. Nearly 90 percent of the subjects became infected with the virus—that is, it started replicating inside their bodies. But only 54 individuals developed actual cold symptoms. And who were those people? The ones who slept the least.
Once all the data were tallied, the study showed that people who slept less than 7 hours a night were three times more likely to develop cold symptoms than people who averaged 8 or more hours of sleep a night. And subjects whose sleep was disturbed or broken up fared even worse: subjects who reported spending more than 8 percent of their time in bed tossing and turning had a nearly six-fold greater risk of developing a cold (called sleep efficiency). The study, which was reported in the Archives of Internal Medicine in 2012, is thought to be the first to show that such a small sleep deficit can compromise the immune system.
“People who slept less than 7 hours a night were three times more likely to develop cold symptoms.”
And if you regularly forgo some sleep because you feel okay even without a full 8 hours, consider this: Cohen found that “feeling rested” was not protective. The only measures that mattered in preventing infection were getting more than 7 hours and sleeping efficiently.
Dr. Cohen’s study is a wake-up call about the impact sleep has on our day-to-day health. But the bigger problem with lack of sleep is looming years down the road, thanks to all the ways sleep deficits build up in your body and slowly erode your health and vitality. At some point, you just may wonder if all those late nights with Jay Leno and Facebook were really worth it.
Another study looking at the difference in getting just an hour or two less sleep found that people who slept the least had the greatest buildup of calcium in their arteries—a known precursor to heart disease—5 years later. Nearly 500 people age 35 to 47 participated in the study, conducted at the University of Chicago Medical Center. They wore wristbands to measure sleep and had CT scans before and after the study to measure calcium buildup in their arteries.
Over the 5 years, artery calcification was detected in 27 percent of the subjects who slept 5 hours a night, but in only 6 percent of those who slept 7 hours a night. The study authors believe the results may stem from the fact that blood pressure falls when sleeping, so more sleep means more time in each 24-hour period with low blood pressure.
“Artery calcification was detected in 27 percent of the subjects who slept 5 hours a night, but in only 6 percent of those who slept 7 hours a night.”
Maybe the chance of developing heart disease years from now won’t get you to shut off the tube or computer and get some shut-eye tonight. But how about getting fat? Would that do it? Numerous studies have found that people who don’t get enough sleep tend to be heavier. You might have noticed this yourself. When you don’t sleep well, you’re often hungrier the next day; crave sugary, fatty foods; and don’t get the feeling of being satisfied.
If so, you’re not alone. A study published in The American Journal of Clinical Nutrition in 2011 observed that sleep-deprived subjects consumed, on average, 300 more calories a day. A study conducted at the Mayo Clinic found that being restricted to two thirds of their usual sleep time made people eat an average of 549 extra calories a day! Still another study done at Brigham and Women’s Hospital and published in 2012 found that subjects whose sleep patterns were not only shortened but also moved around in a 24-hour period, to mimic jet lag or variable work shifts, showed decline in metabolic rate big enough to cause a 10- to 12-pound weight gain in a year.
If scientists don’t know why we sleep, or how we sleep, do they at least know why not sleeping makes us eat more? The mechanism underpinning this unfortunate relationship appears to be hormonal.
Several studies have shown that lack of sleep raises the production of ghrelin, a hormone produced in the digestive tract that’s responsible for making you feel hungry. At the same time, poor sleep lowers levels of leptin, a hormone made by fat cells that tells you when you’re full and gives you a feeling of satisfaction with what you’ve eaten. These are complicated signals to figure out, and the research is far from clear. But whatever the underlying reason, the science is abundantly clear that if you don’t sleep enough, you’re likely to eat more, eat worse foods, and gain weight.
“The science is abundantly clear that if you don’t sleep enough, you’re likely to eat more, eat worse foods, and gain weight.”
It should come as no surprise, then, that the University of California, San Francisco, teams who have done so much work measuring telomeres have also found that women with poor sleep habits have—you guessed it—shorter telomeres. What was interesting about this study was that it found the biggest difference in telomere length was related not to the duration of sleep, but to a woman’s perception of how well she slept, according to the study’s lead author, Dr. Aric Prather. The study adjusted the data to remove the effect of stress, which is known to shorten telomeres, and found poor sleep quality still had an impact on telomere length.
Of course, this study provides doubly bad news for people with chronic stress, because they are exactly the population who tends to have trouble sleeping, Dr. Prather says.
Problem Sleep: Cause and Cure
There are only theories about why and how we sleep. Scientists know that getting stretches of uninterrupted sleep is critical for solidifying memories, for example. Mice woken up repeatedly can’t remember the toys they played with the day before. But obviously, there’s something more crucial going on. Sleep is so essential that a rare genetic disorder, appropriately called fatal familial insomnia, eventually robs people of the ability to sleep and results in certain death, usually within a year. Lab animals, too, when deprived of sleep, quickly succumb to one disease or another.
As to what makes us fall asleep, the answers are no clearer. Lemont Kier, professor of medicinal chemistry at Virginia Commonwealth University, has theorized that a buildup of nitrogen in our brains each day from breathing the air around us—which is 78 percent nitrogen—gradually anesthetizes the brain and puts us to sleep. Only after a period of slow, shallow breathing during sleep does the nitrogen dissipate.
With so few concrete answers to fundamental questions about sleep and lots of novel theories, scientists worry that people don’t take sleep as seriously as they should. Scientists don’t know, for example, why one person needs less sleep than another, but some do. There are even so-called elite sleepers who can get by with just 2 or 3 hours of sleep a night and experience no sense of sleep deprivation and no ill health effects. Those people tend to know who they are, but doctors and scientists have no way to test for it. And most people who say they don’t “need” 8 hours of sleep probably do; they just power through the feelings of sleepiness, extra hunger, and lack of focus, perhaps assuming that’s what “normal” feels like.
But even if we can’t figure out what makes us sleep, can we at least figure out what makes us sleep badly? There are some clues, but like the process of aging, it seems to be a complex symphony of factors. For example, scientists have identified a few variants of genes that are associated with poor sleep ability, but that doesn’t necessarily mean if you have those genes you won’t be able to sleep well. Brain structure also seems to play a role. And other researchers have identified a greater need for sleep when the brain has been exercised through learning new things and having new experiences, which could explain why the elderly often sleep poorly.
And then there are more provocative studies that seem to get at the very nature of being human. As social creatures through the millennia, loneliness appears to be particularly damaging to human health: lack of social connectivity leads to dementia, heart disease, even slow wound healing. Scientists have connected these outcomes to lack of sleep.
A 2011 study published in the journal Sleep compared feelings of loneliness to a person’s sleep quality in two distinctly different groups: undergraduate college students and members of a South Dakota religious community called the Hutterites. The Hutterites live in close-knit groups of extended families who share every aspect of their lives with one another, from work to meals to religious observance.
Despite that social closeness, though, some Hutterites still express feelings of loneliness. So do some college students, obviously. There simply are some people who have difficulty feeling satisfied with their social connections, no matter what their level of social interaction. The significant finding in the study was that for both the Hutterites and the college students, despite living in vastly different lifestyles, those who felt the loneliest were the people who experienced the most fragmented sleep.
The authors of the study suggest that this fragmented sleep, known to cause major health problems, could be the mechanism that makes loneliness or depression affect someone’s health. In other words, maybe it’s not the loneliness itself that leads to poor health outcomes, but the poor sleep quality common among those who suffer from such psychological distress.
“Maybe it’s not the loneliness itself that leads to poor health outcomes, but the poor sleep quality common among those who suffer from such psychological distress.”
The science that seems to hold the most promise for the sleepless is the study of sleep solutions. People simply need more sleep. Forget about why they do, and figure out how they can get it.
Sleep disturbances come in many forms: insomnia; sleep apnea (constant waking due to interrupted breathing and low oxygen levels); interrupted sleep from frequent or prolonged awakenings; perceived poor sleep quality, or not feeling “rested” after sleep; daytime sleepiness; and more.
There is no one answer for all these ills, but a few things come close, such as exercise and limiting activities such as working, emailing, eating or drinking, and exercising before bed. Stress-reduction exercises, such as cognitive therapy, meditation, and relaxation techniques, have also been shown in studies to help even chronically bad sleepers get more sleep.
But it can become a vicious cycle: when you don’t sleep well, you don’t have the willpower or motivation to exercise or take care of yourself, so you sleep less and then get further entrenched in bad habits. The good news is, according to research psychologist Aric Prather of UCSF, “it’s one of the few health behaviors that people want to do more of. You get pleasure from it, so it’s a little easier to get someone motivated.”
Dr. Prather and other sleep specialists suggest that many normal, healthy people who may think they have a medical sleep problem actually have a more conventional sleep problem, which is that they’re stuck in a cycle of too little sleep, low motivation, high stress, poor presleep behaviors, and the possible use of sleep medications that can be addictive.
It may seem insurmountable, but if you haven’t been diagnosed with a genuine sleep disorder, such as obstructive sleep apnea, you can start making an effort to break the cycle of viewing sleep as a second-rate activity. Making it a priority should become your priority. If you tend to stay up late to get a little extra work done, remember, scientists have proved that a good night’s sleep will make you more focused and productive the next day, and that’s the best way to get more work done. With every good night’s sleep you’re also building your brain’s defenses against dementia, regulating your diet, becoming happier, and, most likely, prolonging your life.
Shutting your eyes and shutting down for at least 7 hours a night is not a short-term need to get you through the next day; it’s a long-term requirement to get you through the full span of your life.