The pressure to be more productive often makes people wonder if they can train their bodies to get by with less sleep. Stories of highly successful people who claim to sleep only four or five hours a night make the idea sound tempting. However, scientific evidence shows that while the body can adapt to many things, reducing your actual need for sleep is not one of them.
Sleep is a biological requirement, not just a habit. According to the Centers for Disease Control and Prevention, most adults need at least seven hours of sleep each night to maintain proper health. Studies published in Sleep have shown that individuals who restrict their sleep to six hours or less over a period of two weeks perform just as poorly on cognitive tasks as those who went without sleep for two full nights. What makes this more concerning is that participants often believed they had adjusted to sleeping less, even as their performance declined, showing that the body does not truly adapt but instead accumulates sleep debt.
There are very rare exceptions. Research led by Dr. Ying-Hui Fu at the University of California, San Francisco, discovered a gene mutation in a small population of people known as “natural short sleepers.” These individuals function normally on about four to six hours of sleep without suffering the usual cognitive or health declines. However, this genetic trait is extremely uncommon and cannot be trained or developed through lifestyle changes. For the vast majority of people, trying to cut back on sleep comes with serious health consequences.
Chronic sleep deprivation increases the risk of several health issues, including cardiovascular disease, diabetes, obesity, and impaired immune function, as noted in research from Nature and Science of Sleep. It also disrupts hormone regulation, leading to higher cortisol levels and altered metabolism. Even moderate reductions in sleep can result in mood disturbances, memory problems, and slower reaction times, which can affect both daily functioning and long-term health.
What you can train is your sleep efficiency. By following good sleep hygiene practices—such as keeping a consistent sleep schedule, limiting caffeine and alcohol intake before bedtime, avoiding screens in the evening, and creating a cool, dark sleep environment—you can improve the restorative quality of your sleep. This may help you feel more refreshed and energized, but it does not reduce your body’s actual sleep requirement.
The bottom line is that for most people, the idea of training the body to need less sleep is a myth. Sleep is essential for brain function, physical health, and emotional well-being. Instead of cutting back on hours, the focus should be on improving sleep quality so that the time spent in bed truly restores the body and mind.
Disclaimer: This article is for informational purposes only and should not be considered medical advice. If you are experiencing chronic fatigue or difficulty sleeping, consult with a healthcare professional for proper evaluation and guidance.
References:
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Centers for Disease Control and Prevention. (2022). How much sleep do I need? Retrieved from https://www.cdc.gov
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Van Dongen, H. P. A., Maislin, G., Mullington, J. M., & Dinges, D. F. (2003). The cumulative cost of additional wakefulness: Dose-response effects on neurobehavioral functions from chronic sleep restriction and total sleep deprivation. Sleep, 26(2), 117–126.
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Fu, Y. H., Xu, Y., Garfinkel, M., & Ptáček, L. J. (2019). Short sleep: Genetic basis and clinical implications. Nature and Science of Sleep, 11, 111–118.
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Goel, N., Basner, M., Rao, H., & Dinges, D. F. (2013). Circadian rhythms, sleep deprivation, and human performance. Progress in Molecular Biology and Translational Science, 119, 155–190.