Sleep Deprivation’s Ancient Advantage

Sleep deprivation benefited our ancestors, yet harms us now — but staying fit may help us cope

Less sleep needed: An ancestral gift

Our ancestors traded sleep for productive nightly activities like exchanging cultural information to gain social and individual learning, watching for predators and strengthening bonds with peers. This learning had evolutionary benefits and led natural selection to favor shorter sleep durations. Humans are outliers, needing sleep for only seven hours, far less than the predicted 9.55 hours of sleep for a primate with similar traits to ours.

Our ability to thrive with longer waking hours is thought to be possibly due to our highest proportion of efficient, dreamy REM sleep amongst all studied primates and brain anatomy changes that facilitate essential housekeeping functions of sleep (like removal of toxins) in a shorter span. This ancestral choice to sleep less was worthwhile (although some speculate that it may also have had drawbacks).

Less sleep available: A modern misery

In an extreme example of sleep deprivation, in 1964 Randy Gardner broke the world record by staying awake for 11 days. His wake-a-thon bit him back years later in the form of unbearable insomnia that changed his personality. He referred to it as a “karmic payback” in a 2018 interview with NPR’s Hidden Brain podcast.

Today, despite knowing its benefits, humans still willingly sacrifice sleep. We forgo sleep to pull an all-nighter in preparation for an exam or a meeting, binge-watch TV shows or scroll through social media.

Sleep is not a luxury for people who must face sleep disorders, socioeconomic sleep disparity, new parenthood or work obligations of pilots, health-care workers and others with irregular hours. One-third of Americans and Canadians are short of sleep.

Considerable research shows that sleep deprivation impairs communication between brain regions and brain blood flow, damage to various parts of the brain and a buildup of toxins that may contribute to mood disorders and a higher risk of chronic diseases.

Exercise caution

We cannot conclude that higher fitness is a cause of memory protection during sleep deprivation. Other healthy habits of fitter participants such as good sleep hygiene, higher cognitive reserve and healthy diet may have contributed to their better memory performance despite sleep loss.

However, animal research has shown that aerobic exercise training — which increases cardiorespiratory fitness — can protect against the detriments of sleep deprivation. These findings synergize with our own and suggest possible forward steps in dealing with the epidemic.

Compromising sleep has not served our ancestors and us equally. Nature’s incessant drive to choose sleep underscores its irreplaceability. But today, if you decide to run a wake-a-thon, it is advisable to stay fit!

Conclusion

Sleep is a fundamental aspect of human life, yet we often prioritize it secondarily to other activities. The negative consequences of sleep deprivation are numerous, including impaired brain function, reduced productivity, and increased risk of chronic diseases. Staying fit through regular exercise can potentially mitigate some of these effects, but more research is needed to fully understand the relationship between sleep, physical fitness, and brain health.

FAQs

Q: How does sleep deprivation impact brain function?
A: Sleep deprivation can impair communication between brain regions, reduce cognitive function, and lead to increased risk of mental health disorders.

Q: What is the recommended amount of sleep for adults?
A: The recommended amount of sleep for adults is 7-9 hours per night, although individual sleep needs can vary.

Q: Can staying fit help cope with sleep deprivation?
A: Research suggests that aerobic exercise training, which increases cardiorespiratory fitness, can help mitigate some of the negative effects of sleep deprivation. However, more research is needed to confirm this relationship.

Q: Who is more likely to experience sleep disorders?
A: People with sleep disorders, socioeconomic sleep disparity, new parenthood or work obligations of pilots, health-care workers and others with irregular hours are more likely to experience sleep disorders.

Q: Why do our ancestors sleep less than we do?
A: Our ancestors slept less than we do due to their survival needs, which led to adaptations that favored shorter sleep durations.

Note: The content provided is solely for informational purposes and does not constitute medical advice. It is important to consult a healthcare professional for personalized sleep-related advice.