Dispelling a sleep myth: We sleep far less than we evolved to

It’s often assumed that humans used to sleep far more before the modern world disrupted our natural rhythms. But is this true?

What does the evidence say?

While it’s impossible to measure sleep in prehistoric humans, we can learn from studies of contemporary hunter-gatherer societies. Research on groups across different continents suggests they sleep, on average, between 5–7 hours per night—comparable to, or even slightly less than, the modern average. These communities typically go to sleep around 3.5 hours after sunset and do not wake in the middle of the night.

Where did this myth come from?

Historical records describe cultural variations in sleep, such as medieval Europeans engaging in a short period of activity during the night. However, these accounts come from anthropological and literary sources rather than objective measurements, making it difficult to know how widespread these patterns really were.

We also sleep significantly less than other primates. Chimpanzees, for example, get around 10–12 hours of sleep per night. If we compare ourselves to them, it’s easy to feel as though we’re missing out. However, our shorter sleep duration appears to be a long-standing evolutionary trade-off rather than a recent loss.

Sleep and workplace wellbeing

Sleep isn’t just a personal health issue—it’s a key workplace risk factor. Poor sleep affects decision-making, reaction times, and mental resilience, all of which impact productivity and wellbeing.

At MOAI Health, we help organisations understand and mitigate workplace risks—including sleep, stress, and other psychosocial factors—through our expert training programmes. Find out how we can support your team.

References:

1. Yetish, G., Kaplan, H., Gurven, M., Wood, B., Pontzer, H., Manger, P. R., Wilson, C., McGregor, R., & Siegel, J. M. (2015). Natural Sleep and Its Seasonal Variations in Three Pre-industrial Societies. Current Biology, 25(21), 2862–2868. https://doi.org/10.1016/J.CUB.2015.09.046
2. Ekirch, A. R. (2016). Segmented Sleep in Preindustrial Societies. Sleep, 39(3), 715. https://doi.org/10.5665/SLEEP.5558

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