Why do we sleep? How much is enough? Do we die if we don’t get enough?

Kate Rusk, Joe Alcock, Coffee Brown and Gandhi Yetish discuss these topics in this episode of the EvolutionMedicine podcast.

Sleep is one of the least understood lifestyle-related risk factor for chronic disease. For instance, it has been well established that smoking reduces lifespan and increases the risk of chronic inflammatory diseases and cancer. Same goes for certain diets. The opposite is true for exercise. Now we can add disrupted sleep to the list of risk factors for chronic disease and shortened lifespan. Read Disruption of Circadian Clock Linked to Obesity, Diabetes and Heart Attacks. The question is, why?

The sleep and activity tracker Jawbone (interestingly this company and its products are having some recent issues) released some data showing the ideal amount of sleep for a happy mood (above). This result, from a large sample makes it appear that sleep duration has a prominent effect on mood.

Work done by Gandhi Yetish PhD tried to answer the question: how much sleep are we evolved to need? He compared sleep in  modern industrialized populations in comparison to diverse hunter gatherer populations. The answer: about 6 hours! This is similar to us industrialized humans with all our artificial lights, crazy work schedules, and so on.

Read Yetish et al Current Biology 2015 here.

Other evolutionary work has centered on the uniquely human habit of nesting on comfortable beds, unlike other primates. We seem to prioritize sleep more than our closest relatives? Why?

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Joe Alcock

Emergency Physician, Educator, Researcher, interested in the microbiome, evolution, and medicine