Sleep is among the most important pillars of good health, right up there with eating well and getting plenty of physical activity. Yet while we might know what goes into our bodies, and we surely know if we’ve exerted ourselves, we’re largely clueless about what happens when we’re sleeping and — here’s a zinger — we don’t even know how much we sleep or how good it is.
In a new study, scientists in Japan monitored brain waves of sleeping people with electroencephalography (EEG) devices, then asked them how they thought they had slept. The participants’ subjective ratings rarely matched the reality of their sleep quality — how deep it was — or how much they were awake during the night. The key findings:
“66% of individuals who perceived their sleep as poor exhibited no objective sleep problems, while 45% of those who considered their sleep sufficient were identified as potentially sleep deprived.”
Now that you know what you don’t know, let’s bust some serious sleep myths because, well, I think we can all sleep better knowing the truth.
Most people don’t get enough sleep
Totally false.
Statistics on insomnia are all over the ballpark, with some putting the prevalence as high as 42% of the population. The numbers are almost always based on self-reporting, and as we just learned, that’s an unreliable measure. Among the most commonly cited stats: One-third of people don’t get enough sleep. Even if that’s true, simple math reveals that two-thirds of people are doing just fine, sleep-wise.
Regardless, the “one-third” stat is not accurate. The surveys and analyses behind it actually found that one-third of people (or thereabouts—various studies have generated different numbers) aren’t getting the recommended amount of sleep, which is often put, for study purposes, at 8 hours, and yet as we’ll see below, that’s not a firm threshold by which to measure sufficient sleep.
One study, published in the journal Sleep Medicine Clinics [PDF], sought to evaluate existing research to arrive at more accurate figures for insomnia. The conclusion: “Approximately 10% of the adult population suffers from an insomnia disorder and another 20% experiences occasional insomnia symptoms.”
False impressions about human slumber have been cultivated by the sleep industry, tweaking the language in their favor and even cherry picking studies that in some cases they have funded, all to encourage sales of sleeping pills, better mattresses, and other products most people don’t need.
People need 8 or 9 hours of sleep
Largely untrue, very misleading.
Again, the sleep industry is partly to blame for claims that cite these numbers, and they’ve been repeated so often — even by respectable science organizations and some scientists in their journal papers — that they’re a copy/paste staple of many stories about sleep.
Fact is, 7 to 8 hours is ample for most adults, top sleep experts agree. Some can do just fine on less, some may need a bit more. Young adults definitely need more, a distinction that’s rarely made.
Now, it’s true that less than 7 hours for adults is linked to poorer health outcomes, but that’s an average that does not apply to every individual. Plus it’s notoriously difficult to establish cause-and-effect because most of the research involves surveys and other self-reporting.
While we’re on the subject: If you need 9 hours or more of sleep every night, and you’re beyond your mid-20s, there’s a reasonable chance you have an underlying health condition that needs addressing, or that your sleep tendencies indicate you’re apt to develop a health problem. Studies have indicated that people who sleep too much — typically defined as around 9 hours or more — are at higher risk for heart disease, cognitive decline and even more frequent infections.
You can do just fine in 6 hours or less
False for most people, and definitely a serious health risk.
There’s considerable research linking this low level of sleep duration to countless physical and mental health conditions, from heart disease to dementia. This low level of sleep leaves people moodier, less productive, and less able to make good decisions. Put starkly, adults who sleep less than 6 hours a night are 13% more likely to die before their time, compared with those who sleep seven to nine hours, an overview of existing research found.
Again, the research speaks to averages — not every person is affected exactly the same — and cause-effect is difficult to establish. But the preponderance of evidence, and advice from every sleep expert I’ve ever interviewed, makes clear that getting less than 7 hours is probably not super healthy for most people, and less than 6 is flirting with disaster.
Naps are good for you. Naps are bad for you
Both claims could be true or false.
If you’re unable for whatever reason to get sufficient sleep at night, a nap could be beneficial. However, naps can also be an indicator of poor sleep habits, and experts agree that addressing the underlying issues in order to sleep better at night is a much better solution than trying to nap your problem away.
Also, some people seem genetically more inclined to successful napping. Their naps tend to be brief and light, and they wake up refreshed. Other people fall into a deeper sleep, and upon waking (or having to be woken) they can feel groggy for hours.
“I consider napping to be a good thing, but it needs to be taken in the context of the person and his or her own sleep cycles and body,” says Charlene Gamaldo, MD, medical director of Johns Hopkins Sleep Disorders Center.
If you nap, sleep experts advise keeping it under 30 minutes and aim to get it done by mid-afternoon, so it doesn’t impinge on your night sleep.
REM sleep is the most important stage
Misleading.
The rapid-eye movement (REM) stage of sleep is indeed very important. It’s when we dream, and when the mind works through emotions and consolidates memories and puts them into long-term storage, getting you mentally ready to tackle another day.
But the totally separate stage of deep sleep is equally important, if not more so. During deep sleep, also called the slow-wave stage, your brain is functioning at its lowest ebb, and body temperature and breathing rates are at their lowest. This is when the glymphatic system, the janitor of the physical brain, cleans out misfolded proteins and chemical toxins that build up during the day. Simultaneously, a chemical cleaning occurs throughout all the cells of your body, too, rejuvenating your muscles and all your organs.
REM sleep isn’t so hard to come by. But deep sleep can be elusive, especially if you drink too much alcohol, wrestle chronically with stress or anxiety, don’t get much physical activity, or otherwise build up too much sleep kryptonite. Getting enough deep sleep has a direct effect on how rested and ready to go your mind and body feel the next day.
Problem is, while you are asleep, you can’t properly measure what stage you are in. Sleep-tracking watches can give you an indication, but they are not accurate at measuring deep sleep. Shy of visiting a sleep clinic where they measure brain waves, the only way to know if you’re getting enough deep sleep is, in fact, how you feel during the day.
Old people can’t sleep well
Totally false for most.
Again, what happens to some people tends to get generalized, often for marketing purposes. The majority of older people sleep just fine. Surveys actually indicate that people 65 and older get more sleep than any other age group. As with people of any age, seniors who don’t sleep well often have underlying conditions that thwart their sleep. Lack of physical activity or insufficient time spent outside in natural daylight are among them. Also, chronic pain and numerous sleep-thwarting diseases are more common as we age.
Still, midlife is when people sleep worst, research has shown. And if you’re stuck in midlife, you probably know why, what with all the pressures of your job, kids, family and maybe even taking care of your parents.
If you’re older, and you don’t sleep well, don’t assume that’s normal. Study up on good sleep habits or talk to a qualified physician about your sleep problems.
Night owls cannot become morning people
False, but with a grain of truth.
Many night owls are genetically programmed to sleep at what other people would consider odd hours. Many of them like it that way, and that’s just fine. But if being a night owl causes problems with your day job, or you simply run out of time to sleep sufficiently, health risks rise considerably. The good news is that research suggests it’s possible for most night owls to shift their bedtime an hour or two earlier.
Scientists recruited 22 night owls who’d been going to bed around 2:30 a.m., on average, and who usually woke up after 10 a.m. By changing a few habits — including exercise, exposure to more daylight and fixed wake-up times and bedtimes — the volunteers moved their sleep window ahead by 2 hours.
“Notably, the phase advance was accompanied by significant improvements to self-reported depression and stress,” the researchers reported, “as well as improved cognitive (reaction time) and physical (grip strength) performance measures during the typical ‘suboptimal’ morning hours.”
Sleeping pills can be useful
Dangerously false for most people.
Sleeping pills range from ineffective to risky to deadly, and one of their most common side effects — next-day grogginess — would be funny if it weren’t so serious. For the most part, they simply do not work as advertised, science has demonstrated.
“Although sleep problems can happen at any age and for many reasons, they can’t be cured by taking a pill, either prescription, over-the-counter or herbal, no matter what the ads on TV say,” says Preeti Malani, MD, a University of Michigan physician.
If under direction of a physician you find that a sleeping pill helps, just know that its effectiveness is likely to decrease with time. And before you pop any, consider the known side effects. People who take prescription sleep aids are much more likely to fall and break a hip, develop dementia, do insane and dangerous things while sleep-walking, and die sooner than people who avoid them.
Melatonin supplements are totally safe
Mostly true for adults — if used in moderation — but dangerously misleading for kids.
Melatonin is a naturally occurring hormone produced mostly in your brain to help make you sleepy at night. It’s governed primarily by the cycle of natural outdoor daylight and darkness, which keeps the mind-body circadian rhythm well timed to promote sleep and wakefulness. Melatonin supplements in small doses (less than what’s often in the products) can serve as a temporary sleep aid, such as when you fly across time zones or otherwise shift circadian gears (shift workers come to mind).
Long-term use is thought to be less effective and should be considered only in consultation with a physician or sleep expert. Melatonin should not be a go-to solution for chronic insomnia.
The effect of melatonin supplements on young, developing brains is unknown, so pediatricians as well as sleep scientists advise against giving it to children. Even for adults, long-term use has not been properly studied, but there are hints of possible side-effects, including inflammation of the intestines.
Oh, and most melatonin supplements don’t contain what they claim. Some have less melatonin than what the label says, some have way, way more. Since supplements are not regulated by the FDA, you also can’t trust that they don’t contain other drugs or unhealthy ingredients — a common problem with supplements, multiple studies have shown.
People often say they’d like to get more sleep—that much is true. But what most of us should really focus on is getting better sleep, making more efficient use of that time in the sack. Creating a cycle of good sleep starts by getting up at a consistent hour, spending time outside, moving more, eating well, avoiding alcohol, dealing with life’s challenges or letting things be rather than ruminating on them, and sticking to a consistent bedtime. Better days cultivate better nights, which cultivate better days, which…
Your support makes my reporting and writing possible. To make your days better, check out my book: Make Sleep Your Superpower. And if you’re a writer, see my Writer’s Guide newsletter. — Rob