To Fix Our Modern Sleep We Should Look to the Past: A Critical Look at Hunter-Gatherer Sleep Challenges Our Modern Assumptions
Do you struggle to get quality sleep? You are not alone. Although sleep is an essential process that we were all born knowing how to do, in the US today over half of us report difficulty falling and/or staying asleep. The root of modern sleep issues might be a disconnect between our evolved sleep patterns and contemporary lifestyles coupled with a misunderstanding of what healthy sleep actually looks like.
To improve sleep, it’s crucial to understand it as a passive process influenced by external factors — similar to how our breathing adjusts to different conditions. Our sleep is affected by stress, age, exercise, diet, social connections, hormones, timing, weather, season, moon phase and so much more. When sleep problems arise, it means one or more of these inputs are off or that our expectations for our sleep are not realistic.
Research on hunter-gatherer sleep patterns offers valuable insights into how our ancestors likely slept and challenges our modern expectations of what sleep should look like. Although hunter-gatherers sleep in communal beds with significantly more disruptions and exposure to the elements than modern humans, they do not complain about sleep difficulties and have exceptional metabolic, cardiovascular and general health.
Here are some key insights from hunter-gatherer sleep research that challenge modern expectations and recommendations for sleep quality and quantity:
- DURATION: Hunter-gatherers sleep on average 6–7 hours per night, with 7–9 hours in bed.
- QUALITY: They often spend 30–40% of the night awake with multiple wake-ups each night.
- REGULARITY: Wake-up times are very consistent, with hunter-gatherers varying their rise times on average by 30 minutes over the month. Bedtimes vary significantly more, often linked to availability of evening light from the lunar cycle. Sleep is an hour or more longer in the winter compared to the summer
- ALERTNESS: Naps are common, occurring on at least 50% of days in one study and for an average duration of around 45 minutes.
- TIMING: Essentially all hunter gatherer nighttime sleep occurs between the hours of 8PM and 8AM. While there is variability in chronotype (early vs. late habitual sleep timing) between individuals, habitual sleep timing is determined by age, with adolescents/young adults going to bed and rising later than older hunter gatherers.
Based on this hunter-gatherer sleep research, I think it is safe to say that our modern sleep expectations — uninterrupted 7–9 hours nightly, sleeping through the night, keeping both a regular bedtime and wake-up time — do not reflect the only healthy way to sleep.
Another theme from hunter-gatherer and cross-cultural sleep research is that human sleep is flexible and can adapt to changing environmental conditions. If you live somewhere too hot and sunny for afternoon activity, you might find a shorter nocturnal sleep period paired with an afternoon siesta works best. Prefer staying cozy in bed to avoid the cold and dark? This could lead to “biphasic” sleep, with two separate nocturnal sleep periods. Need to stay up late for a few nights to complete a project? Your sleep-wake system will allow you to do so, then provide a few nights of catch-up sleep. If you need to be alert during the night due to a Red Flag fire warning, your brain will naturally wake you more frequently and keep your sleep lighter to increase your awareness. Traveling across the world to a time zone 12 hours off? Your sleep-wake system will adjust, allowing you to get some rest and eventually realign with the new time zone. The human sleep-wake system is remarkable in its adaptability, and rigid expectations for sleep patterns fail to recognize this inherent flexibility.
Here are my recommendations for creating the conditions for healthy sleep in our modern lives, building on the lessons of hunter-gatherer sleep:
1. Set a Consistent Wake-Up Window:
Choose a 30-minute window for waking up and stick to it every day, regardless of how well you slept. Hunter-gatherers’ consistent wake-up times are driven by natural cues like temperature, sunlight, and social interactions. Our modern sleep environments largely shield us from these cues, so we may need to use an artificial cue (aka an alarm clock) to keep this level of regularity. Avoiding black out shades to let a bit of sunlight seep into your room and sleeping with the windows open if air quality and noise pollution allow is also ideal.
2. Allow a Flexible Bedtime:
Recognize that your sleep needs may vary depending on your recent sleep durations, season and other factors. Try to reconnect with your brain’s natural sleepiness cues and go to bed only when you are sleepy. If external factors keep you up late, still get up around your regular wake-up time and add an afternoon nap, or go to bed earlier if your brain sends you sleepiness cues at an earlier time. One caveat: if you are getting sleepy relatively early in the evening and waking up earlier than desired or falling into a “biphasic” sleep pattern with a period of prolonged wakefulness during the night, recognize that this is a normal adaptation to a prolonged period of nighttime darkness. If you would like to reduce wakefulness during the night or not wake up so early, simply reduce the duration of nighttime darkness by keeping things brighter in the evening until 8 hours before your target wake-up time.
3. Get Morning and Daytime Sunlight Exposure:
Get outside or at least maximize indoor lighting within the first hour of waking for at least 10–30 minutes. The more time you spend outdoors during the day while the sun is out (with appropriate sun protection), the stronger your sleep-wake system will be and, research shows, the better your health.
4. Address Anxiety:
Manage generalized and situational anxiety with evidence-based psychotherapy strategies such as Cognitive Behavioral Therapy, Acceptance and Commitment Therapy and Mindfulness Based Stress Reduction. (My personal favorite place to start is by reading “The Happiness Trap” by Russ Harris.)
5. Understand Normal Sleep Patterns:
Accept that sleep varies nightly based on daily inputs. Both rest and sleep are vital and it is normal to be awake for portions of the night. Remember what hunter-gatherer sleep looks like and how sleep can look different in different cultures. Reassure yourself that your brain is smart and is giving you the sleep it thinks you need, based on the inputs it has received during the day and night.
6. Eat a Diet Rich in Plants, Move Your Body, and Socialize with Others
Ancestral humans (and modern day hunter gatherers) consume a tremendous variety of unprocessed and minimally processed plants each day. They also move their bodies and naturally obtain a combination of low impact, flexibility, cardiovascular and resistance training throughout their day. Hunter gatherers live in groups and the rhythms of the group have a profound impact on the timing of their activities and overall health. Diet, exercise and social interaction all have direct effects on our sleep-wake system and here again we would be wise to follow the patterns of our ancestors.
By understanding ancestral human sleep and adjusting expectations for modern sleep, we can improve our sleep quality and overall well-being. Embracing the flexibility and adaptability of the sleep wake-system can help us move away from rigid sleep norms and towards a more natural, restorative sleep experience.
