When you’re not getting enough sleep, everything can feel more challenging. A poor night’s sleep leaves you feeling tired and sluggish and affects all aspects of your mental and physical performance. One late night can throw you off for a day or two, but when your sleep is chronically short, the list of adverse side effects grows substantially.
While you may already be aware of the recommendation to get at least 7 hours of sleep each night, it might not be as clear what the potential pitfalls are if you don’t. Many people, including high-level CEOs, productivity gurus, and grinders, claim to not only survive on only a few hours of sleep but thrive on it.
Recently, Dr. Matthew Walker, Ph.D., Professor of Neuroscience, New York Times bestseller, and author of “Why We Sleep” has gone viral on TikTok due to his bold claims about the dangers of too little sleep. He says the percentage of people who can get under 6 hours of sleep without impairment is 0% and that sleeping this little increases your risk of cardiovascular disease or heart attack by a staggering 200%.
So who is correct, and does everyone need 6 or more hours of sleep to function optimally and remain healthy? We asked the experts.
How Much Sleep Do People Really Need?
Health authorities and current research stress that all adults need 7 to 8 hours of sleep a night. However, in economically advanced societies, the amount of sleep per night statistically decreases, Dr. Candice Stewart, DNP Bio-hacking and longevity expert & owner of Stella Capri Wellness points out. “In the U.S., 79% of the population; in the Uk, 70%, and in Japan, 90% of the population sleep less than eight hours,” she says.
Further research reports 21% of those in the United States, 19% in Japan, and 18% in the United Kingdom sleep fewer than six hours each night during the work week, which is the level at which Dr. Walker says severe health consequences arise.
Risks of Getting Less Than 6 to 8 Hours of Sleep
According to Stewart (and the science), sleep is the most critical factor in longevity and a healthy life, followed by eating healthy and exercising. “Getting less than 6 hours of sleep has devastating consequences for longevity,” she says.
“Chronic sleep deprivation can have grave health consequences, including cognitive function impairment, mood disorders, and more severe outcomes such as cardiovascular disease, diabetes, and an increased mortality risk,” warns Dr. Patrick Porter, neuroscience expert and founder of BrainTap. Adding to those risks are immune system impairment, mood disorders such as anxiety and depression, reduced libido, and a greater likelihood of developing Alzheimer’s and dementia.
Sleep Quality Matters Too
The true essence of sleep health lies not just in the number of hours but in the quality of sleep and its various stages, according to Porter. “It’s not strictly about needing 6 or 8 hours of sleep; we need around 1 to 2 hours of deep delta sleep for the brain’s detoxification process, and about 2 to 4 hours of REM sleep to process our day, organize information, sequence our dreams, and plan for tomorrow,” he explains.
During a typical night’s sleep, we cycle through various stages, including deep and REM sleep. These stages are not just crucial for rest and rejuvenation, but they also serve to regulate our neurochemistry. When we don’t cycle through these stages due to inadequate sleep or poor-quality sleep, this neurochemical balance is disrupted. Porter adds that if we wake up in an upcycle, we carry energy throughout the day.
REM sleep is vital in re-energizing your mind and body, particularly the amount of deep sleep you get, which is the most restorative and rejuvenating sleep stage. “During deep sleep, your blood pressure drops, heart and breathing rates are steady, arm and leg muscles are relaxed, and it’s harder for you to wake up,” says Stewart. During deep sleep, your muscles grow and repair, the immune system is refreshed, and the brain flushes out toxins.
Focus on Quality and Quantity for Longevity, Mood, and Health
“Sleep is the cheapest bio-hack for longevity you can do; getting 8 hours of sleep a night has many benefits for your brain and cognitive ability,” says Stewart.
Neurotransmitters, such as serotonin and dopamine, are predominantly produced in the gut and play crucial roles in mood regulation, cognitive function, and our ability to handle daily stress. Inadequate or poor-quality sleep may disrupt the production of these neurotransmitters, impairing our ability to cope with stress and negatively affecting brain function.
If this becomes chronic, it can have far-reaching impacts on mental health, leading to chronic stress, anxiety, and even symptoms of dementia. “Good sleep hygiene is not just about feeling refreshed in the morning; it’s a fundamental aspect of our overall mental and physical well-being. It further emphasizes the importance of not just the quantity but also the quality and the structure of our sleep,” says Porter.
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Sources
Stewart, Candice. Author interview. June 2024.
Besedovsky, L., Lange, T. & Born, J. Sleep and immune function. Pflugers Arch – Eur J Physiol 463, 121–137 (2012). https://doi.org/10.1007/s00424-011-1044-0
Porter, Patrick. Author interview. June 2024.
Cara C Tomaso and others, The effect of sleep deprivation and restriction on mood, emotion, and emotion regulation: three meta-analyses in one, Sleep, Volume 44, Issue 6, June 2021, zsaa289, https://doi.org/10.1093/sleep/zsaa289
Cho JW, Duffy JF. Sleep, Sleep Disorders, and Sexual Dysfunction. World J Mens Health. 2019 Sep;37(3):261-275. https://doi.org/10.5534/wjmh.180045
β-Amyloid accumulation in the human brain after one night of sleep deprivation. Shokri-Kojori E, Wang GJ, Wiers CE, Demiral SB, Guo M, Kim SW, Lindgren E, Ramirez V, Zehra A, Freeman C, Miller G, Manza P, Srivastava T, De Santi S, Tomasi D, Benveniste H, Volkow ND. Proc Natl Acad Sci USA. 2018 Apr 9. pii: 201721694. doi: 10.1073/pnas.1721694115. [Epub ahead of print] PMID: 29632177.
