In a culture of demanding jobs, tech dependence and caffeine addiction, many people turn to sleep medications. But the trappings of modern life may not be behind modern sleeplessness.
A new study found that three ancient societies of hunter-gatherers living in three different parts of the world today didn’t get any more sleep than modern societies. These pre-modern people slept 6.5 hours a night on average, didn’t take regular naps, went to sleep an average of three hours after the sun went down — and still managed to wake before dawn.
"The short sleep in these populations challenges the belief that sleep has been greatly reduced in the 'modern world,'" said lead study author Jerome Siegel, PhD, of the University of California, Los Angeles, in a press release. "This has important implications for the idea that we need to take sleeping pills because sleep has been reduced from its 'natural level' by the widespread use of electricity, TV, the Internet and so on."
For this study, Dr. Siegel and team looked at the sleeping habits of the Hadza of Tanzania, the San of Namibia and the Tsimane of Bolivia. For 1,165 days, the sleeping habits of 94 individuals from these tribes were recorded.
Dr. Siegel and team found that group sleep amounted to between 5.7 and 7.1 hours on average each night. The time between the beginning and end of sleep periods amounted to between 6.9 and 8.5 hours on average. Both of these amounts were lower than average durations reported in industrial societies, according to these researchers.
The hunter-gatherers also slept an hour longer in the winter. None of the groups went to sleep when the sun went down.
According to Dr. Siegel and colleagues, these findings suggest that sleep patterns may have more to do with temperature and light, as all of the groups went to sleep as the temperature fell and slept through the coldest part of the day.
Unlike the sleepers of modern society, however, very few hunter-gatherers had insomnia — a sleep disorder that affects many US adults.
"Despite varying genetics, histories, and environments, we find that all three groups show a similar sleep organization, suggesting that they express core human sleep patterns, probably characteristic of pre-modern-era Homo sapiens," Dr. Siegel said. "Mimicking aspects of the natural environment experienced by these groups might be effective in treating certain modern sleep disorders, particularly insomnia, a disorder affecting more than 20 percent of the US population."
This study was published Oct. 15 in the journal Current Biology.
The National Institutes of Health, the National Institute on Aging and the National Research Foundation of South Africa funded this research. No conflicts of interest were disclosed.
