Could Ancient Sleep Habits Offer Clues for People With Insomnia?

For anyone who regularly wakes up during the night and immediately worries that something has gone wrong with their sleep, evolutionary anthropologist David Samson has an intriguing message: uninterrupted sleep may not have been the norm throughout much of human history. His research into hunter-gatherer communities and human evolution suggests our ancestors developed sleep that was shorter, more flexible, and sometimes considerably more fragmented than the idealized eight uninterrupted hours many people pursue today.

Samson, an associate professor at the University of Toronto and author of the 2026 book The Sleepless Ape: The Story of Sleep in Human Evolution, has spent years studying how humans came to sleep so differently from other primates. His models suggest humans might be expected to sleep roughly 10½ hours based on comparisons with other primates, yet the human average across cultures is closer to seven hours. Humans also spend a greater proportion of that shorter sleep period in REM sleep than other primates, according to Samson.

That doesn’t mean people with insomnia should simply accept persistent sleep problems or deliberately start sleeping less. Instead, Samson’s work raises a different possibility: some modern expectations surrounding the “perfect” night’s sleep may themselves contribute to anxiety when normal awakenings happen. Ancient and traditional sleep patterns offer clues about flexibility, natural light, social connection, and circadian rhythms that could help people reconsider how they approach rest.

Humans Haven’t Always Slept Eight Uninterrupted Hours

One of the biggest differences between modern sleep advice and the environments Samson has studied is how much activity surrounds sleep. Instead of retreating alone into a completely dark and silent room, people in small-scale communities may sleep in dynamic social environments where others are nearby and nighttime awakenings aren’t necessarily treated as a failure. Samson told CNN that despite having empirically more fragmented sleep, hunter-gatherers he has spoken with overwhelmingly report liking their sleep.

Research supports the idea that human sleep can be remarkably flexible. A study led by Samson in a nonelectric rural community in Madagascar found participants averaged about 6.5 hours of nighttime sleep and napped on 89% of recorded days. Researchers also observed a peak in nighttime activity after midnight on 49% of nights, a pattern consistent with segmented sleep. Despite shorter and more fragmented sleep, their circadian rhythms were more stable across days than those typically documented in postindustrial populations.

Samson’s evolutionary explanation goes much further back. As early humans moved from sleeping in trees to sleeping on the ground, he argues that fire, shelter, group sleeping, environmental preparation, and people with different sleep schedules helped create a protective social environment. Someone within a group could often be awake while others slept, potentially allowing individuals to safely enter deeper and more vulnerable stages of sleep.

Natural Light May Be One of the Most Useful Ancient Clues

Of all the lessons Samson has taken from his research, light has had one of the biggest effects on his own routine. He told CNN that improving his relationship with light dramatically improved his sleep. Instead of relying entirely on alarms and blackout curtains, he prefers allowing natural sunlight to help signal when his body should wake, maintaining stronger cues from the outside environment.

That matters because light is a major environmental signal for the body’s circadian system. Samson points out that many people in industrialized societies now spend more than 90% of their time indoors, potentially weakening the natural environmental cues that once helped synchronize sleeping and waking with the 24-hour day. His argument isn’t that everyone should abandon modern bedrooms, but that paying attention to the timing of light exposure may be more useful than obsessing exclusively over achieving a perfectly uninterrupted block of sleep.

Social surroundings may matter as well. Samson describes ancestral sleep as occurring inside a kind of protective “shell” created by shelter, fire, environmental preparation, light, and lookouts. Modern bedrooms obviously don’t need to recreate prehistoric camps, but his research suggests that feeling secure and maintaining strong day-night cues may be important pieces of sleep that aren’t captured simply by counting hours.

Ancient Sleep Doesn’t Mean Ignoring Persistent Insomnia

There is an important distinction between learning from ancestral sleep and assuming chronic insomnia doesn’t matter. Sleep remains essential for physical and cognitive health, and Samson’s argument isn’t that everyone should intentionally shorten their sleep or force themselves into a segmented schedule. His broader research instead shows that human sleep evolved to be unusually flexible and that there probably isn’t one ancestral schedule everyone needs to recreate.

For someone who occasionally wakes during the night, that perspective may at least make the experience feel less unusual. Historical and cross-cultural evidence shows that nighttime wakefulness, daytime naps, and segmented sleep can all occur within human sleep patterns. But persistent difficulty falling asleep, staying asleep, or functioning during the day can still warrant professional attention rather than simply being attributed to human evolution.

The most practical lesson from Samson’s work may therefore be less about copying exactly how ancient humans slept and more about reconsidering what “good sleep” has to look like. Strong natural light cues, regular circadian timing, a sense of safety, social connection, and less anxiety about occasional awakenings all fit more comfortably with humanity’s evolutionary history than chasing an absolutely silent, isolated and perfectly uninterrupted night every time your head hits the pillow.