Most of us are well versed with the importance of sleeping properly for at least 7 to 8 hours every day. Yet, 30 to 35% of American adults struggle with brief symptoms of insomnia while 10% suffer from chronic insomnia disorders.1
It is true that a sound night’s sleep grows more and more elusive as we age. But what if we told you that this may have nothing to do with insomnia at all, rather, it may actually be an age-old survival mechanism?
What Research Says
A study conducted by Duke University tracked the slumber patterns of 33 healthy adults from Tanzania’s Hadza tribe who are modern hunter-gatherers. These people survive by foraging their food – namely berries, tubers, meat, and honey in the woodlands of the savanna, near Tanzania’s Lake Eyasi and its neighboring areas. During the night, they reunite in the same place where the children and the adults of the tribe sleep together.
It is important to note that while these tribals are as modern as us, they still live the lifestyle of our ancient ancestors. They live in huts made of twigs, branches, and woven grass, sleep on the ground, and have no access to electricity or controlled climatic conditions. Like our ancient ancestors, these tribals allow their sleep patterns to be governed by the natural patterns of day and night.
Details Of The Research
The researchers discovered that the sleep patterns of the Hadza tribe were almost never in sync. On an average, the participants who went to bed right after 10 pm woke up around 7 in the morning, while some preferred retiring as early as 8 pm and woke up by 6 am. On the other hand, some stayed up until past 11 pm and woke up after 8 in the morning.
In between, the participants woke up multiple times during the night. Some stayed in bed, tossing and turning, while some got up to either smoke, tend to a crying baby, or to relieve themselves before falling asleep again. Hence, it was rare to find a moment when every single participant of the study was out cold all at one time. A total of 220 hours were spent in observing the participants’ sleep patterns. Yet, it was found that all the adults were only fast asleep simultaneously for 18 minutes. On an average, more than a third of the group was found alert, or snoozing very lightly, at any given time.
These observations were only confined to the healthy adults and did not include children sick or injured people, or even children. Also, these healthy adults with intermittent sleep patterns did not complain of sleep problems.
What Do These Findings Mean?
The findings suggest that unsynchronized sleep schedules and nights of restless sleep may be an evolutionary leftover from neanderthal times many, many years ago, when a wild beast lurking in the shadows may try to encroach into your space and eat you at 2 am.
One might wonder why the Hadza tribe don’t have people dedicated to guarding the group at night, especially since they live in such an unprotected environment. But the truth is, they don’t really need to.
Researchers explain that the natural variation in the sleep patterns of each older adult of the group paired with phases of light or restless sleep is more than enough to ensure that there’s at least one person who is on guard at all times of the night. It goes without saying that when one is in REM (rapid eye movement) sleep, which is the deepest stage of the sleep cycle, you’re pretty much dead to your surroundings. It is true that REM sleep helps you consolidate memories, improves your learning and cognitive abilities, and helps you be in better control of your emotions.
However, in order to enter into REM sleep, you need to begin and continue sleeping securely. Therefore, from an evolutionary standpoint, it is suggested that the older adults are naturally designed to have brief moments of sleeplessness or light sleep, thus being more attuned to any kind of potential threat, so that they may protect the younger members of the clan who are naturally designed to have longer hours of deep slumber.
The findings of this study are not entirely new, and in fact, back those of the famous Sentinel Theory from 1966, where similar sleeping behaviors were observed in group-dwelling animals.2
Poorly Sleeping Grandparent Hypothesis
The researchers also propounded a ‘poorly sleeping grandparent hypothesis’ where they reached a conclusion that these incredibly asynchronous sleep patterns were a natural part of the aging process. They observed that participants who were in their 50s and 60s mostly went to sleep earlier and woke up much earlier than their younger counterparts in their 20s and 30s.3
This shows that once again, from an evolutionary standpoint, people preferred living in mixed-age groups where the grandparents who were more of ‘morning larks’ kept watch over the younger members of the group who were more of ‘night owls.’
If you’re a healthy, older adult and are experiencing frequent phases of sleeplessness or light sleep, it is not entirely necessary that there is something wrong with you. Instead, know that it is probably an effective survival mechanism that was handed down to you from your early ancestors.
If you begin to feel that your disturbed sleep patterns are interfering with your day to day functioning, try techniques like meditation, yoga, or exercise to help you sleep better at night. Practising proper sleep hygiene and sticking to a sleep schedule every day is also very effective in helping you get more quality shut-eye.
If none of this works and you’re still worried, don’t hesitate to seek a medical opinion from a certified professional.
|↑1||Insomnia Awareness Day facts and stats. American Academy of Sleep Medicine.|
|↑2||Samson, David R., and Charles L. Nunn. “Sleep intensity and the evolution of human cognition.” Evolutionary Anthropology: Issues, News, and Reviews 24, no. 6 (2015): 225-237.|
|↑3||Humans Evolved For Better Sleep In Less Time. Duke Today.|