Harvard Professor Challenges Eight-Hour Sleep Recommendation
In a recent episode of the podcast Diary of a CEO, Dr. Daniel Lieberman, a professor at Harvard University’s Department of Human Evolutionary Biology, questioned the commonly held belief that people need a full eight hours of sleep each night. Dr. Lieberman argues that most individuals actually perform better on seven hours of sleep.
The idea of requiring eight hours of sleep has been around since the industrial revolution when manufactured light, electricity, phones, and televisions became prevalent. However, Dr. Lieberman pointed out that populations without access to these modern technologies have been found to function well on six or seven hours of sleep.
Studies conducted on individuals who lack electricity and do not have access to TVs or phones have revealed that they consistently sleep for six or seven hours a night without the need for naps. This challenges the notion that natural human beings require a full eight hours of sleep.
Dr. Lieberman also suggested that limiting screen time can lead to a decreased need for sleep in the long run. This recommendation aligns with the guidelines from the Centers for Disease Control and Prevention (CDC), which advise Americans to aim for seven to nine hours of sleep each night.
While Dr. Lieberman’s recommendation falls on the lower end of the CDC guidelines, recent research supports his theory. A study published in the journal Nature Aging found that seven hours of sleep is the optimal amount for middle-aged and older adults. Deviating from this amount, whether getting more or less sleep, has been associated with cognitive difficulties, symptoms of depression and anxiety, and other health problems.
Despite the mounting evidence supporting the benefits of seven hours of sleep, a large portion of the American population remains sleep-deprived. According to CDC figures, one-third of Americans aged 18 to 64 are not getting sufficient sleep, and even among adults over 65, more than a quarter report inadequate sleep.
Sleep deprivation has long been linked to chronic health issues such as heart disease, kidney disease, high blood pressure, diabetes, stroke, obesity, and depression. However, there are some exceptions to the seven-hour rule. Individuals who are ill may require more sleep, and different populations, such as teenagers and older adults, may have varying sleep schedules.
For a restful night’s sleep, the American Academy of Sleep Medicine advises maintaining a consistent sleep schedule, going to bed and waking up at the same time every day, including weekends.
With the growing body of research supporting the idea that seven hours of sleep may be optimal for most individuals, it may be time to reconsider the commonly held belief in the magic number of eight hours.