Drunk or just tired? How sleep deprivation affects your cognition.

If you’re a college student, chances are you didn’t get a full eight to ten hours of sleep last night like your doctor recommended. Even for “real-life adults” in the working world, long work hours and the constant buzz of our work emails has extended the working day from a nine-to-five job into a 24-hour marathon. 2018 data from the National Health Interview Survey found that out of 150,000 adults across various occupations, 35.6% self-reported having seven or less hours of sleep (Khubchandani & Price, 2020). That percentage was a 4.7% increase from a prevalence of 30.9% in 2010 (Figure 1). In the past year alone, the shift to remote, at-home work caused by the pandemic has increased the working day by three hours (Davis & Green, 2020). Unless you’ve figured out the secret to a healthy work-life balance, sleep deprivation is a common phenomenon for most of us.


Even outside of work demands, college students are known to stay up late. (Work hard, party hard, right?) For many college students, sleep deprivation is not just a rite of passage but a bragging right. However, staying up all night—whether to study or to party—grants its achiever a hangover that’s not only physical, but mental. Research has found that participants with moderate sleep deprivation had impairments equivalent to participants with alcohol intoxication (Williamson & Feyer, 2000). When sleep deprivation increased to 17 to 19 hours without sleep, participants’ performance was the same as or worse than performance for participants with blood alcohol concentration (BAC) levels of 0.05%, and less than five hours without sleep resulted in performance equivalent to that of a BAC of 0.10%.

Figure 1. Prevalence of short sleep duration in working American males and females (Khubchandani & Price, 2020).

In other words, being sleep deprived negatively affects our cognitive processing to the point that we function just as poorly as someone under the influence. For comparison, most states will charge you with drunk driving when your BAC is 0.08%.

If we judge this level of cognitive impairment to be too risky to drive, then why do we build our society in a way that essentially enforces a level of tiredness that decreases cognitive and performance abilities?

The simplest answer to this query is that we just don’t know enough about sleep. However, neuroscientific research has examined the parallels between decreased performance as a result of sleep deprivation and as a result of alcohol intoxication.

One avenue of further research on the topic examines the relationship that both sleep and alcohol have to adenosine, one of the four nucleosides that make up DNA and is formed in the breakdown of ATP, making it critical in energy transfer processes. Adenosine also acts as an inhibitory neurotransmitter in the brain, working in opposition of excitatory neurotransmitters like glutamate.

Our bodies naturally produce and build up adenosine throughout the day, leading to a literal wave of sleepiness at the end of the night called “sleep pressure.” In contrast to the steady ebb and flow of our natural circadian rhythm, or wake drive, we reach a level of drowsiness that causes us to fall asleep (Figure 2).

Figure 2. Sleep is the result of increasing sleep pressure from increased levels of adenosine, which overtakes the influence of our circadian rhythm, or wake drive (Walker, 2018).

Research by Elmenhorst et al. (2018) explored how the effects of ethanol impair our motor and cognitive performance and decrease our alertness level. Alcohol acts as a depressant on the central nervous system by blocking adenosine reuptake and increasing adenosine formation, an effect visible in molecular brain imaging. Previous studies on alcohol have shown that it makes falling asleep easier and initially increases deep sleep, but goes on to disrupt our sleep later in the night (Dijk et al., 1992; Ebrahim et al., 2013). When comparing the effects of alcohol with the effects of sleep deprivation, evidence suggests that the same increase in regulation of inhibitory cerebral A1 adenosine receptors occurs when we are sleep deprived (Elmenhorst et al., 2018). Thus, decreased performance abilities of sleep deprived participants was comparable to intoxicated participants.

Not only do alcohol intoxication and sleep deprivation disrupt our sleeping mechanisms and impair brain functioning while awake, but the extent to which we are affected by these phenomena goes hand in hand: how we feel after being in either one of these states is determined by individual trait characteristics that make us more or less vulnerable to their effects (Elmenhorst et al., 2018). So the college student recipe for a “good weekend?” Well, it’s not exactly recommended by our current neuroscientific research.

At the end of the day, sleep is important. (And yes, I mean that literally.) If you wouldn’t show up drunk to class, you shouldn’t show up sleep deprived. Figuring out how to avoid sleep deprivation in this economy, though? That’s a topic for another time.


References

Davis, M., & Green, J. (2020). Three Hours Longer, the Pandemic Workday Has Obliterated Work-Life Balance. Retrieved 19 February 2021, from https://www.bloomberg.com/news/articles/2020-04-23/working-from-home-in-covid-era-means-three-more-hours-on-the-job

Dijk D.J., Brunner D.P., Aeschbach D., Tobler I., Borbély A.A. (1992) The effects of ethanol on human sleep EEG power spectra differ from those of benzodiazepine receptor agonists. Neuropsychopharmacology 7:225–232.

Ebrahim I.O., Shapiro C.M., Williams A.J., Fenwick P.B. (2013) Alcohol and sleep I: Effects on normal sleep. Alcohol Clin Exp Res 37:539–549.

Elmenhorst, E., Elmenhorst, D., Benderoth, S., Kroll, T., Bauer, A., & Aeschbach, D. (2018). Cognitive impairments by alcohol and sleep deprivation indicate trait characteristics and a potential role for adenosine A1 receptors. Proceedings Of The National Academy Of Sciences115(31), 8009-8014. doi: 10.1073/pnas.1803770115

Khubchandani, J., Price, J.H. Short Sleep Duration in Working American Adults, 2010–2018. J Community Health 45, 219–227 (2020). https://doi.org/10.1007/s10900-019-00731-9

Walker, M. (2018). Why we sleep. Penguin Books.

Williamson, A., & Feyer, A. (2000). Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occupational And Environmental Medicine, 57(10), 649-655. doi: 10.1136/oem.57.10.649

Source of featured image: Brisbane Headache & Migraine Clinic.

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