You’ll often hear in the media that modern lifestyles have shortened the sleep hours of humans in the 21st century.

According to this view, us modern types are sleep deprived due to the countless “mod cons”, comforts of modern life, such as TVs and mobile phones we watch at bedtime.

Presumably, before modernity, sleep was natural, healthy sleep habits were the norm and our ancestors slept blissfully and long.

But is this actually true? 

Did our ancestors sleep longer than us? Did they get huge quantities of sleep? Were our ancestors mythical “master sleepers”? 
If Methuselah lived to 969 years old, was it because he always made sure he got 8hrs (9hrs? 10hrs?) of sleep? 

With all the worry that people have about their sleep and that they “aren’t getting enough” it’s worth considering what the natural sleep patterns of our ancestors would have looked like. This might also help us understand what we should consider normal sleep for a human, and where we might be going wrong with our modern sleep patterns.

And researchers at UCLA have done exactly this and the results are a “wake up call” for all those worried about not getting enough sleep.

How Our Ancestors Slept: Healthy Natural Sleep Habits

To gain insight into the sleeping habits of pre-modern humans, researchers at the University of California, Los Angeles (UCLA) conducted a wide-ranging study of three traditional hunter-gatherer societies: 

• the Hadza from Tanzania, 

• the San from Namibia, and 

• the Tsimane from Bolivia.

In total, the researchers meticulously collected data from 94 adult individuals covering a period of 1,165 days. With these findings, they were able to develop a comprehensive understanding of how our ancient ancestors likely slept.

The analysis of the three groups yielded an astonishing result:
Despite differences in:

- genetics, 
- backgrounds, and 
- conditions of living, 

the same trends in sleep organization appeared across all three demographics.

This implies that inherent to our species is a uniform pattern of sleep likely dating back to ancient Homo sapiens.

According to lead study author Jerome Siegel, this suggests a deep-rooted core of human sleep patterns.

So what did the study find? 

The scientists found that, on average, traditional people sleep for only around 6.5 hours a night.

The average duration of sleep within the groups fell between 5.7 and 7.1 hours of sleep each night. 

The total sleep period (opportunity for sleep) was around 6.9 to 8.5 hours between the onset and finish of the period. 

The scientists noted that these numbers are actually at the low end of sleep durations reported in "industrial societies." 

"The short sleep in these populations challenges the belief that sleep has been greatly reduced in the 'modern world,'"

says Jerome Siegel of the University of California, Los Angeles.

The study also found that the hunter-gatherers do not include taking a midday nap in their daily routine. 

They also tend to remain up late into the evening.

In fact, despite not having access to artificial light, they reliably stayed up an average of an additional three hours after the sun had set before they would go to sleep.

So far it sounds like their sleep is pretty much the same as modern humans. Right?

But wait. Here’s the difference:

The hunter-gatherers generally woke up before the dawn broke. 

So they were awake before the sun came up (and presumably they didn't sleep in on the weekends).

Late to bed, early to rise.

Similar to modern humans, the study found that the hunter-gatherers slept an average of one hour more during the winter months than they do in the summertime. 

Overall, it appears that the sleep pattern of the tribes was primarily influenced by temperature and not light. The hunter-gathers retired as temperatures fell and slept through the coldest part of night, then rose as the temperature started to rise before dawn.

Healthy Sleep - The Truth About 8 Hours

So it seems that 8 hours of sleep wasn't a thing for our ancestors.

But it gets more interesting.

The hunter-gatherers also differed significantly from the modern populations in another key way: Namely, they do not tend to experience the struggle of insomnia.

The tribes were generally unfamiliar with trouble sleeping and sleep problems. 

Taking the findings together, the study authors noted implications for how we think about sleep and the way healthy sleep is promoted today:

"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."

There's also another intriguing idea offered by the researchers:

"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,"

Siegel says.

The study was published in the journal Current Biology (Yetish et al., 2015).

Clinical Comment

There's a widespread belief in the public that everyone should get eight hours of sleep. Failure to get this sleep time will lead to all manner of disease, immune system impairment, high blood pressure, stroke, diabetes, dementia etc.

Many of our clients are worried enough about not getting 8 hours of sleep they resort to sleep medications and other sedatives.

Yet eight hours of sleep appears to be a modern invention and doesn't actually appear to be the natural pattern of sleep for humans. 

We've previously noted research has found 7 hours appears to be healthiest amount of sleep for an adult. The fact that these tribes naturally sleep around that number supports 6.5 - 7hrs (and below) being the healthiest sleep. 

It's also interesting these tribes do not complain they "can't function" on less than 8 hours of sleep, or that they are "sleep deprived" on 6.5hrs and less on a regular basis. Common complaints we hear in the clinic.

So what do we see as standout points about healthy natural sleep? 

Length of daytime activity: Prior wakefulness is a key determinant of the quality of your sleep and will help you sleep better. If these pre-industrial societies are getting an average of 6.5hrs of sleep a night, that means they typically have a wakeful activity period of around 17.5hrs a day. This is longer than virtually all our insomnia patients and speaks to why these tribes do not experience insomnia (and why modern societies do experience sleep problems).

Consistent sleep schedule: Rising at the same time is fundamental to sleep health (going to bed at the same time isn’t that important overall). The tribes don't stay in bed. Getting up early has been shown to assist in falling asleep easier at the other end of the day. Yet in the modern world we see it as a birthright to sleep in on the weekend, disrupting the consistency of sleep and promoting difficulty sleeping over time.

So we agree with the study investigators that mimicking not only the environment of the tribes but also the sleep/wake pattern habits of the tribes will be effective in treating insomnia, improve your sleep, and promote sleep during the night that is high quality, consistent and of a healthy quantity.

Don’t forget, if you are worried about your sleep we specialise in cognitive behavioral therapy for insomnia (CBT-i) for insomnia - the recommended and most effective treatment for insomnia.

We also do supported medication tapers to get people off sleeping pills.

Research indicates chronic insomnia doesn’t go away by itself so if you’ve been experiencing sleep issues for some time you may wish to consider treatment.

You can get in touch or book an appointment directly.

And we don’t just work with insomnia, we also treat and support other sleep disorders including circadian rhythm sleep disorders and restless legs syndrome. We don’t treat obstructive sleep apnea but can provide info and direction on providers if needed  

Article Author: Dan Ford Sleep Psychologist