Sleep is one of the most effective things we can do each day for the health of our brain and body. Indeed, all of the major functions of the body, and many essential operations of the brain, are improved by sleep when we get it. When we don’t sleep enough, those same functions can become impaired. Here are just three of the many reasons why we need sleep.
Sleep supports immunity
There is an intimate connection between your sleep and your immune health. Sleep strengthens the immune system, helping fight certain infections. For example, those reporting less than 7 hours of sleep were significantly more likely to become infected by the rhinovirus, or the common cold, relative to those sleeping 8 hours or more [1]. In a prospective study of over 50,000 women, sleeping 5 hours or less was associated with a 70% greater likelihood of developing pneumonia, a respiratory infection, relative to individuals getting 8 hours [2].
Sleep enhances learning
Sleep is important to your memory in at least two ways. First, getting sleep before learning helps refresh the hippocampus, a key memory center in the brain. As a result, we wake up with a superior ability to acquire new facts [3]. Second, sleep after learning essentially clicks the “save” button on newly learned facts in an operation called, “consolidation” [4]. In this way, sleep “future-proofs” our memories, making us less likely to forget critical information.
Sleep enhances creativity and productivity
Sleep also appears to inspire creativity. Research shows that people who slept on a new problem were more than twice as likely to find an insightful solution, relative to time spent awake [6]. Some of these benefits may come from REM sleep, often called dream sleep [7]. This may be the reason that we’re never told to, “stay awake on a problem”. Insufficient sleep can also compromise our work performance. For example, shorter sleep predicts lower work rate and slower completion speed of basic tasks. That is, well-rested people may be more productive people [10].
Sleep is therefore a foundation for our physical and mental health, alongside diet and exercise. Understanding the importance of sleep, and investing time to practice good sleep habits, or “sleep hygiene,” can make a real difference in our lives.
Matt is a professor of Neuroscience and Psychology at UC Berkeley, the director of its Center for Human Sleep Science, and the bestselling author of the book Why We Sleep.
References
[1] Cohen, Sheldon, et al. “Sleep habits and susceptibility to the common cold.” Archives of Internal Medicine 169.1 (2009): 62-67.
[2] Patel, Sanjay R., et al. “A prospective study of sleep duration and pneumonia risk in women.” Sleep 35.1 (2012): 97-101.
[3] Krause, Adam J., et al. “The sleep-deprived human brain.” Nature Reviews Neuroscience 18.7 (2017): 404.
[4] Klinzing, Jens G., Niels Niethard, and Jan Born. “Mechanisms of systems memory consolidation during sleep.” Nature neuroscience 22.10 (2019): 1598-1610.
[5] Cai, Denise J., et al. “REM, not incubation, improves creativity by priming associative networks.” Proceedings of the National Academy of Sciences 106.25 (2009): 10130-10134.
[6] Wagner, Ullrich, et al. “Sleep inspires insight.” Nature 427.6972 (2004): 352-355.
[7] Cai, Denise J., et al. “REM, not incubation, improves creativity by priming associative networks.” Proceedings of the National Academy of Sciences 106.25 (2009): 10130-10134.
[8] Engle-Friedman, M, and Riela, S. “Self-imposed sleep loss, sleepiness, effort and performance.” Sleep Hypn 6 (2004): 155-162.
[9] Gibson, M, and Jeffrey S. “Time use and labor productivity: The returns to sleep.” Review of Economics and Statistics 100.5 (2018): 783-798.
[10] Webb, WB, and Levy, MC. “Effects of spaced and repeated total sleep deprivation.” Ergonomics 27.1 (1984): 45-58.