Twenty-four hours in a day usually doesn’t seem like enough to “get everything done,” does it? Exercise and sleep are often sacrificed in our busy lives.
You may think that you’re tough – that you can “get by” on just a few hours of sleep. I assure you, you are wrong. Your “sleep debt” (the accumulated lack of sleep that causes daytime fatigue) will catch up with you.
Consider this statement: “the effects of sleep deprivation are actually so damaging that it is now prohibited as a method of interrogation in most countries.”1
And yet so many of us consistently deprive ourselves of sleep – by choice!
Americans are sleepy people. Sleep studies have revealed that the average American’s sleep debt is likely close to 25-30 hours at any given time.2 According to the National Sleep Foundation’s most recent poll, 63% of American adults report that their sleep needs are not being met, and 43% report that they rarely or never get a good night’s sleep on weeknights. As a result, according to data from the CDC, 37.9% American adults report falling asleep unintentionally during the day in the preceding 30 days – a sign of being dangerously sleep-deprived.2
Daytime sleepiness is dangerous. Inadequate sleep is a health hazard; even worse, the resulting daytime fatigue impairs performance (just like alcohol). Sleep-deprived people perform tasks poorly, make more mistakes, and experience more accidents at work – it’s similar to being intoxicated.3 One Australian study showed that 24 hours without sleep is equivalent to a blood alcohol content of 0.1% (0.08% is legally drunk in most U.S. states) with regard to hand-eye coordination. Being awake for only 17-19 hours still impaired hand-eye coordination – this was equivalent to a blood alcohol content of 0.05%.4 Numerous accidents – of small and large scale – have been attributed to fatigue; from medical errors to plane crashes to the Exxon Valdez oil spill.2
More consequences of inadequate sleep:
- Impaired immune response.5 The quality of sleep before becoming infected is a significant determinant of the severity of cold symptoms. Even one night of inadequate sleep reduces the number and activity of natural killer cells the next day.2
- Impaired learning and cognitive function– blood oxygen levels in the brain are measurably lower after insufficient sleep.6,7
- Increased snacking – lack of sleep results in dysregulation of hunger and satiety hormones.8,9
- Weight gain, impaired insulin sensitivity, and increased risk of diabetes.10-13
- Increased inflammation, high cholesterol, and hypertension.14,15
- Diminished appearance - sleep-deprived people look less healthy and attractive than well-rested people.16
- Emotional disturbances and excessive emotional reactivity.17
- Increased risk of death.18
What is sleep and why is it so important?
The question ‘what is sleep?’ is still somewhat of a mystery. Sleep occurs in 90-minute cycles of REM (rapid eye movement) and non-REM sleep; REM sleep is thought to be the most restorative part of the sleep cycle; REM sleep is thought to contribute to brain development, and almost all dreaming occurs during REM sleep. Tissue repair and growth (in children) is heightened during sleep.2 Also during sleep, our brains ‘stabilize’ newly formed memories, which is one reason why lack of sleep can impair learning (caffeine does not help, by the way). This is thought to occur by the brain ‘replaying’ brain activity from waking experiences during sleep. Interestingly, the greatest impact of sleep deprivation is on memories associated with positive emotions, compared to those associated with neutral or negative emotions.17 Sleep is also thought to fuel creativity, since creativity is dependent on learning, memory, and motivation.2
Sleep, like good nutrition and exercise, is an essential component of a healthy lifestyle. Don’t try to be tough – practice self-care and make sleep a priority. Maybe you didn’t finish everything on your mile-long to-do list. Let it go - you owe yourself some rest!
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3. Swanson LM, Arnedt JT, Rosekind MR, et al: Sleep disorders and work performance: findings from the 2008 National Sleep Foundation Sleep in America poll. J Sleep Res 2011;20:487-494.
4. Williamson AM, Feyer AM: Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occup Environ Med 2000;57:649-655.
5. Opp MR: Sleeping to fuel the immune system: mammalian sleep and resistance to parasites. BMC Evol Biol 2009;9:8.
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13. Patel SR, Malhotra A, White DP, et al: Association between reduced sleep and weight gain in women. Am J Epidemiol 2006;164:947-954.
14. Gangwisch JE, Malaspina D, Babiss LA, et al: Short sleep duration as a risk factor for hypercholesterolemia: analyses of the National Longitudinal Study of Adolescent Health. Sleep 2010;33:956-961.
15. Gangwisch JE, Heymsfield SB, Boden-Albala B, et al: Short sleep duration as a risk factor for hypertension: analyses of the first National Health and Nutrition Examination Survey. Hypertension 2006;47:833-839.
16. Axelsson J, Sundelin T, Ingre M, et al: Beauty sleep: experimental study on the perceived health and attractiveness of sleep deprived people. BMJ 2010;341:c6614.
17. Walker MP: The role of sleep in cognition and emotion. Ann N Y Acad Sci 2009;1156:168-197.
18. Cappuccio FP, D'Elia L, Strazzullo P, et al: Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep 2010;33:585-592.