What people don’t know about healthy sleep — or what they think they know that’s all wrong — may be seriously harming their health.
When researchers examined the most widely held assumptions about sleep with the help of sleep specialists and sleep investigators, they found that many were not supported by scientific evidence, or had been completely debunked by research.
Rebecca Robbins, PhD, of the New York University School of Medicine in New York City, and colleagues rated the top 20 potential sleep myths, based on the strength of the evidence showing them to be false and their potential to cause harm.
At the top of the list was the widely held belief that some people can get by on ≤5 hours of sleep a night for long periods with no impact on health, they reported in Sleep Health.
Robbins told MedPage Today that even people who say they function normally on <7 hours sleep a night are likely to suffer the health consequences of long-term sleep deficits. Studies suggest a link between habitual short sleep duration and increased cardiovascular (CV) and metabolic risk, as well as mental and immunological health disorders.
“I would say the percentage of the population who truly don’t benefit from >5 hours a night of sleep is 0%,” she said. “It would be really nice if we could get the many health benefits of sleep in less time, but there is just no way to do that.”
Robbins said a major goal of the sleep myth study was to begin to change the general mindset about sleep, especially the widely held belief that getting by on less sleep is desirable.
“Sleep is a critical part of a healthy lifestyle. It is just as important, if not more so, as regular exercise or good nutrition,” she said. “It is not something we should try to avoid. It is something we should relish.”
Using internet searches of scientific literature and consumer press, the researchers compiled a list of common convictions about sleep. They then polled 10 experts in the fields of sleep medicine and sleep research to identify sleep myths.
To do this they used the Delphi method, which is a systematic protocol for collecting expert opinions. The potential sleep myths were rated by the experts on their falseness and their public health significance.
Among the most persistent and potentially harmful sleep myths:
Your brain and body can learn to function just as well with less sleep. Overall, the research strongly suggests that while some people do adjust to consistent sleep deficits or circadian misalignment, that does not mean their health will not suffer.
Lying in bed with your eyes closed is almost as good as sleeping. Wrong, Robbins said. Endocrine, CV, and metabolic activity are all very different during wakefulness and non-rapid eye movement (REM) sleep, as is cognition. “Lying in bed for long periods when you can’t sleep is basically the same as going to the gym and standing on the treadmill and not moving,” she said.
And remaining in bed while wishing for sleep can promote anxiety around going to bed each night. This anxiety is common among insomniacs, Robbins said. She said it would be better to get out of bed and find a calm spot and return to bed only when feeling sleepy.
Exercise within 4 hours of bedtime will disturb sleep. Exercise is beneficial for sleep. In addition to being a mood elevator, it improves overall health.
Nevertheless, the sleep experts rated the evidence that vigorous nighttime exercise impairs sleep as inconclusive. So doing some yoga before bed may be more restful than logging 3 miles on the treadmill.
“It may be better to stick to low impact exercise at night,” Robbins said.
Adults sleep more as they get older. Older adults tend to sleep less for a variety of reasons, but it is not yet clear if they actually need less sleep than younger adults.
Drinking alcohol before bed can improve your sleep. It may help people get to sleep, but it is associated with greater sleep disturbance later in the sleep cycle.
“Across a number of different studies and doses, overall, alcohol has a negative overall impact on sleep, delaying the onset of REM sleep. Alcohol consumption has also been found to worsen sleep apnea symptoms,” the researchers wrote.
Robbins said sleep hygiene is often not high on the list of wellness discussions health clinicians have with their patients, but it should be.
“Sleep is still a relatively small field and every day we are uncovering more about the connection between healthy sleep and waking success,” she said. “Most physicians probably did not get a lot of training in sleep because there is so much to cover in medical school.”
She said the growing interest in sleep hygiene, including the burgeoning business interest in promoting good sleep, could change this.