Sleep debt

Image credit: Henry Meynell Rheam [Public domain], via Wikimedia Commons

 

For students across the world, and especially at Berkeley, sleep seems to be a commodity that is scarce. I know that many of us are willing to risk hygiene, public embarrassment, as well as a healthy social life for the chance to eliminate a couple hours of sleep debt. It’s interesting how people speak colloquially about sleep in such economic terms, and you have to admit – the idea of sleep as being a consumable resource with a daily requirement is appealing. The ability to “go into debt” by not getting enough sleep, as well as having the opportunity to “repay ones debt” by sleeping more than our daily requirement, are all concepts that our society, ever obsessed with quantitative data, are happy to embrace. However, is there validity to this school of thought, or is it simply an ever too simple reduction of a physiological process? Our knowledge of sleep is extremely limited. In an interview with National Geographic’s, Dr. William Dement, co-discoverer of REM sleep and co-founder of Stanford Sleep Medicine Center says “As far as I know, the only reason we need to sleep that is really, really solid is because we get sleepy.”

What we do know, is the obvious: researchers have published results in the journal Sleep that “cumulative increase in performance lapses across days of sleep restriction”. The presence of a collective sleep debt is obvious, but is it possible to pay it all back? Does our body work as a literal bank, where if we are 10 hours in debt, we will continue to feel its effects in the future?As it turns out, this question is much more difficult to answer.

One researcher, Dr. Paul Shaw of Washington University in St. Louis, has turned to Drosophila melanogaster (the fly) as a model organism to study sleep. A protein named Amylase, found in the saliva of both humans and the fly, seems to be a quantitative indicator for measuring sleep deprivation. According to Shaw, Amylase’s salivary activity, as well as its concentration, is highly correlated with sleep drive. Identifying a biological marker such as Amylase is only the first step in the struggle to understand sleep debt. Researchers are currently looking for other markers to validate the use of Amylase. Current approaches to studying sleep deprivation rely on subjective tests, and adopting a more quantifiable approach is the first step to helping the sleep-deprived population of the United States. The CDC found that “among 74,571 adult respondents in 12 states, 35.3% reported <7 hours of sleep during a typical 24-hour period, 48.0% reported snoring, 37.9% reported unintentionally falling asleep during the day at least once in the preceding month”. These statistics are harsh, but further emphasizes the importance of catching up on sleep. Though your body’s need for sleep may not be as well defined as a bank account, catching up on lost sleep is still a good way to recover from a long week of midterms.

 

References

 

The Secrets of Sleep: http://ngm.nationalgeographic.com/2010/05/sleep/max-text

Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night: http://www.ncbi.nlm.nih.gov/pubmed/9231952

Identification of a biomarker for sleep drive in flies and humans: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1750902

Behavioral Risk Factor Surveillance System (BRFSS) survey: http://www.cdc.gov/features/dssleep/

 

 

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