En español | For years, we’ve been told getting enough sleep will help us stay healthy, sharper and more positive in our outlook. Now, new research suggests it may be a matter of life and death for one group: middle-aged adults with high blood pressure, type 2 diabetes or heart disease.
Folks with any of these health problems who clocked less than six hours a night had twice the risk of dying from heart disease or stroke over three decades compared with those who got more than six hours. Short-sleepers who already had a history of heart disease or stroke fared even worse: They had nearly three times the increased risk of dying from cancer.
“Getting enough sleep is important for everybody, obviously, but it’s particularly important for those who already have heart disease or diabetes,” says lead study author Julio Fernandez-Mendoza, associate professor at Penn State College of Medicine and a sleep psychologist at Penn State Health Milton S. Hershey Medical Center.
What the study found
The study looked at more than 1,600 adults between the ages of 20 and 74, with a median age of 47, who were divided into three groups: those with stage 2 high blood pressure (blood pressure over 140/90) or type 2 diabetes, those who already had heart disease or had had a stroke, and those without any of these conditions. Patients were studied in a sleep lab for one night between 1991 and 1998, then tracked through 2016. During that time period, there were 512 deaths, a third from heart disease or stroke and a quarter from cancer.
Why the link to cancer in particular? “We know people who don’t have enough sleep have higher rates of inflammation in their body, which may in turn spur the growth of cancerous cells,” he explains. It may also worsen inflammation that already exists among people with high blood pressure, heart disease or type 2 diabetes.
Unlike those with risk factors for cardiovascular disease, however, otherwise healthy short sleepers didn’t appear to have an increased risk of developing and dying from cancer, heart disease or a stroke. As Fernandez-Mendoza notes, “These people may just be naturally short sleepers.”
That said, other recent studies have found a link between short sleep and risk of heart disease even among those with no risk factors. A U.K. study published last month in the Journal of the American College of Cardiology, for example, examined the sleep habits of over 400,000 people between the ages of 40 and 69 and found that sleeping less than six hours a night raised the risk of a first heart attack by 20 percent compared with those who clocked between six and nine hours. “We also know that lack of sleep as well as poor quality sleep is linked to greater amounts of beta amyloid and tau proteins in the brain, which raises risk of Alzheimer’s,” explains Michael Breus, a Los Angeles sleep specialist and author of The Sleep Doctor’s Diet Plan.
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What the research means for you
If you have high blood pressure, type 2 diabetes or preexisting heart disease, and have trouble sleeping — either difficulty getting enough rest, or feel that you’re not getting good quality sleep — then it’s time to see a sleep specialist, says Breus. A specialist can screen you for sleep disorders such as sleep apnea or restless legs syndrome that can make it tough to get your needed rest.
If you don’t have these risk factors, it’s still important to get a good night’s snooze. While you may not necessarily need exactly eight hours of sleep every night, you do need enough so that you wake up on your own in the morning, without needing an alarm, advises Breus. If you’re having trouble falling or staying asleep, try these strategies:
Set a consistent sleep and wake-up time. When sleep has a regular rhythm, your biological clock will be in sync and the rest of your bodily functions will run smoothly. “When a train in Grand Central is an hour late, it throws all the other trains behind it off schedule as well,” explains Breus. “The same holds true for our bodies.” Even if you go to bed a bit later — say, on the weekend — make sure that you still wake up at roughly the same time.
Drink wisely. If you’re having trouble falling or staying asleep, put the kibosh on caffeine after 2 p.m. “Caffeine has a half-life of about eight hours,” Breus explains, so if you drink a cup of coffee at 3 p.m., you’ll still feel its effects until about 11 p.m. He also recommends having your last cocktail about three hours before bedtime: While alcohol can make you sleepy, it also keeps you from reaching the deep stages of sleep.
Exercise strategically. Staying active has been shown to improve insomnia and sleep quality in general, but try not to break a sweat right before bed, which can rev you up. Try to squeeze in your workout at least two hours before you hit the sack, advises Breus. For the best results, make sure you include both aerobic exercise and resistance training: Both promote good sleep.
Eat a light dinner. Opt for a meal that’s high in fiber and low in saturated fat. Folks who did so fell asleep faster and reported better quality sleep than when they ate a larger, higher-fat one, according to a 2016 study published in the Journal of Clinical Sleep Medicine. Craving a snack before bedtime? Consider munching on two kiwis or sipping cherry juice. Both helped people with insomnia fall asleep and stay asleep longer, according to another 2016 study published in Advances in Nutrition.
Dim the lights. A couple hours before bedtime, limit your exposure to blue light, which comes from TV and electronic screens such as your cell phone, iPad or Kindle. It suppresses the sleep-inducing hormone melatonin, says Breus. This includes outdoor lights, as well: Older adults exposed to higher levels of this type of artificial light at night were more likely to have to rely on sleep medicine to nod off, according to a study published last year in the Journal of Clinical Sleep Medicine.
Get your vitamin D levels checked. Vitamin D deficiency is linked to short sleep duration, especially in people over age 50, according to a 2017 study published in PLOS One. It’s also important to make sure you’re getting enough vitamin B6, since it helps your body produce sleep-promoting hormones such as serotonin and melatonin, adds Breus. You can find it in fish, starchy veggies (like potatoes) and some non-citrusy fruits. (Avoid supplements, since too much vitamin B6 in them has been linked to insomnia.)