The sleep industrial complex is lying to you — and it's making Americans sicker

Adults accept it as conventional health wisdom that we require eight hours of sleep each night in order to be healthy. Yet an expert on human evolutionary biology recently argued that this might actually be misleading.

“Do you lose sleep over whether you sleep too little or too much?” Daniel E. Lieberman, a professor at Harvard University, wrote for The New York Times on Sunday. “You can now relax, because scientists have figured out precisely how much sleep you really need. In a recent study in Nature, an international team of experts reports that the ‘sweet spot’ for adults is between 6 hours 24 minutes and 7 hours 48 minutes. Less or more than this ‘Goldilocks’ zone is associated with faster rates of aging in the brain, heart, liver and other vital organs, plus higher rates of illnesses such as heart disease and depression, and ultimately shorter lifespans.”

Lieberman added that a recent study analyzed self-reported sleep habit data from hundreds of thousands of people. It found that people who sleep more than 8 hours per night suffer health problems just like their counterparts who sleep less than 6 hours and 24 minutes per night. In theory, this would demonstrate that excessive sleep can hurt a person’s health just as much as insufficient sleep.

“However, a major concern with the study is that it analyzed only associations and cannot distinguish between cause and effect,” Lieberman wrote. “Since people who don’t feel well often sleep more, it’s possible that more than 7.8 hours of sleep was falsely identified as detrimental. Another drawback is that the study used notoriously inaccurate self-reported sleep data. (Do you know exactly how much sleep you got last night?) An additional flaw is that the researchers included mostly people of European ancestry. Even so, the study adds substantially to evidence of the health benefits of sleeping enough but not too much.”

Despite these doubts about the dangers of excessive sleeping, Lieberman nevertheless urged readers to monitor their sleeping habits and raise concerns to their doctors about possible underlying health issues that may be at work if someone sleeps too much. He added that, on top of this, Americans need to be aware of the rising epidemic of sleeplessness.

“Maybe learning how lack of sleep accelerates aging will serve as a wake-up call to those who shortchange themselves on sleep and induce them to go to bed earlier,” Lieberman wrote. “Perhaps the relatively small percentage of people prone to oversleeping will set their alarm clocks to get up earlier. My worry, though, is with the roughly 35 percent of Americans who say they get less than seven hours of sleep, many of whom have insomnia.”

He added that when people suffer from insomnia, “emphasizing that their lack of sleep might send them to an early grave could increase their anxiety and stress about sleep, thus exacerbating the problem. Anxiety and stress are major risk factors for insomnia because they stimulate the body to produce hormones such as cortisol that arouse us. Studies have shown that medicalizing sleeplessness sometimes worsens the problem by treating a common issue as a medical matter requiring diagnosis and treatment.”

At the same time, Lieberman said that people should not fret if they fail to get exactly eight hours of sleep. Instead what they need to do is ask themselves basic questions about how their day-to-day health is or is not impaired by their quantity and quality of sleep.

“Are you satisfied with your sleep?” Lieberman wrote. “Do you stay awake all day without dozing? Are you asleep between 2 a.m. and 4 a.m.? Do you spend less than 30 minutes awake at night? Do you get between six and eight hours of sleep?”

He continued, “If your answers to these questions are not ‘usually’ or ‘always,’ then I hope you find relief through well-studied, effective approaches that reduce sleep-related anxiety and stress. These include developing good habits such as exercising, cognitive behavioral therapy and maintaining a regular sleep schedule.”

Speaking with this journalist for Salon in 2023, the inventor of the CPAP — a medical device used to treat sleep apnea — explained that the prevalence of that disorder, in which people frequently wake up at night due to their airways shutting, explains a wide range of other common health problems.

"I've spent a lot of my career looking at pediatric sleep apnea, sleep disorder breathing, and I do think that trying to intervene early, identifying kids who have the risk factors, gives us a chance of preventing it," Sullivan said at the time. "There's no doubt that the size and shape of the upper airway is important. Some orthodontic procedures actually can be very effective. And I think if we can identify earlier, we have a chance of preventing it."

"I don't think the significance of sleep apnea is still fully grasped often by the medical profession," Sullivan explained. "One of the issues that I've become aware of is that I think snoring and sleep apnea put you at risk of getting a number of diseases. I still am astounded when I see patients who have got various cardiac conditions and no one's really looked at or even asked them about what happens to them at nighttime in terms of sleep."