10 Things You Didn't Know About Sleep

Medically Reviewed By William C. Lloyd III, MD, FACS
Written By Elizabeth Beasley on September 3, 2020
  • man-sleeping-on-side
    Sleep: Your Health Depends On It
    Researchers are discovering what William Shakespeare wrote is true: “We are such stuff as dreams are made on and our little life is rounded with sleep”. The study of sleep has made huge advances over the past few decades and we’re understanding more about the scientific value of a good night’s rest. We humans spend 36% of our lives sleeping--and new research explains why getting enough shut eye is essential to our physical and mental health during the other 64%.
  • peaceful-woman-sleeping-in-bed
    1. Sleep cleans your brain.
    Researchers at the University of Rochester Medical Center discovered that while you sleep, your brain washes away toxins that contribute to the loss of brain function and Alzheimer’s disease. A study on mice shows a system in the brain similar to the lymphatic system that opens during sleep and flushes the brain with fluids to clear out toxic by-products of the day’s neural activity. This nightly self-cleaning keeps our mind healthy and sharp as we age.
  • Woman Sick in Bed With Tissues
    2. Sleep keeps colds away.
    Scientists in Germany have proposed that a restful sleep gives your immune system time to store memories of infection so your body can build up defenses to fight the same illnesses in the future. So when facing your next bout with a cold or flu, calling in sick and napping the day away might be even more beneficial than you think. 
  • woman-sitting-up-in-bed-with-insomnia
    3. Some parts of your brain stay awake.
    Many people think your entire brain shuts down when you close your eyes at night, but neuroscientists at MIT have found that a special neural circuit can actually put specific parts of your brain to sleep while other sections stay awake. A new study has shown this holds even more true when you sleep in a new place. In an attempt to protect the body from possible threats, half of the brain stays more awake and alert when you sleep in a new environment. That explains why you might hear more strange noises and not sleep as soundly when you’re away from home.
  • Spending money
    4. Sleep can make you richer.
    Researchers at University of California-San Diego compared average sleep times to earning and discovered if sleep-deprived people add an hour of sleep a night, they could increase their wages by 16%. Getting enough sleep means you can think more creatively, absorb new information better, and make fewer errors when performing complex processes. Even if you can’t sleep on the job, it might boost your paycheck to catch some extra Zs when you’re off-duty.
  • Couple lying on bed in furniture store.
    5. Your bed is a big deal.
    Your mattress can have a big impact on how well you sleep. Research suggests that a medium-firm mattress is ideal, since it doesn’t put too much pressure on sensitive spots like the back and neck. However, firmness will feel different to a 150-pound woman than it does to a 250-pound man. Since everybody (and every body) is different, test drive a few mattresses before you make a final decision.
  • woman-getting-restful-sleep
    6. Sleep locks in information.
    Not only does sleep flush out toxins, but it helps new information stick in your mind. Slow-wave and REM sleep both boost long-lasting recall of information, skills and experiences you collect during the day. When you drift off, your mind replays the day’s events, and the hippocampus and neocortex communicate to consolidate and store what you’ve learned. That’s why it’s easier to recall information for a test if you get a good night’s sleep after you study. 
  • Sign with a number, 7
    7. Seven is your lucky number.
    New research reveals seven hours of sleep provides the biggest health benefit. Studies show getting roughly seven hours a night reduces mortality rates and improves cognitive performance. Too little or too much sleep can increase your chance of experiencing health issues like obesity, diabetes and cardiovascular disease. So shoot for seven hours of shut eye to keep your body at its best. 
  • woman-pushing-cart-through-grocery-aisle
    8. Diet can disrupt your sleep.
    You are what you eat, and what you eat is how you sleep. A study involving 35-year-old adults suggests eating more fiber can lead to more deep sleep, while higher saturated fat consumption can reduce the amount of time in this slow-wave sleep phase. Eating more sugar may also disrupt a good night’s sleep by causing you to wake up more frequently. A low-fat, low-sugar diet can help your body fall asleep faster, stay asleep longer, and feel better overall.
  • standing on scale
    9. Sleep extremes can pack on the pounds.
    Not only can your diet sabotage your snooze time, but sleeping less than five hours or more than nine hours a night can increase your risk of gaining weight. Studies show regular sleep deprivation increases craving for high-calorie foods and carbohydrates. The amount of sleep you get affects hormones that regulate hunger and stimulate the appetite, so not getting enough rest might actually make you eat more. Lack of sleep also leads to fatigue, which often results in decreased physical activity. 
  • Couple sleeping in bed
    10. Women may need more sleep than men.
    New research shows women need 20 to 60 minutes more sleep per night than men. Studies have revealed that because the female brain does a high amount of multitasking during the day, women need extra sleep for proper brain restoration and recovery. Researchers did note that men who perform complex tasks during the day may also need more rest, but still not as much as women.
10 Things You Didn't Know About Sleep

About The Author

Elizabeth has been writing for Healthgrades since 2014 and specializes in articles about alternative and complementary therapies like meditation, yoga, energy work and aromatherapy. She also performs improv comedy and is a firm believer that laughter really is the best medicine.
  1. Is too little sleep a cause of weight gain? Mayo Clinic. http://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/sleep-and-weight-gain/faq-20...
  2. Key Facts and Figures. The Sleep Council. http://www.sleepcouncil.org.uk/feature-pack/key-facts-and-figures/
  3. Prevalence of Healthy Sleep Duration among Adults — United States, 2014. Centers for Disease Control and Prevention. http://www.cdc.gov/mmwr/volumes/65/wr/mm6506a1.htm
  4. The Secret to Memory? A Good Night’s Sleep. BrainFacts.org. http://www.brainfacts.org/sensing-thinking-behaving/sleep/articles/2015/the-secret-to-memory-a-good-...
  5. Sleep: An Overview. BrainFacts.org. http://www.brainfacts.org/sensing-thinking-behaving/sleep/articles/2012/sleep-an-overview/
  6. How many hours of sleep are enough for good health? Mayo Clinic. http://www.mayoclinic.org/healthy-lifestyle/adult-health/expert-answers/how-many-hours-of-sleep-are-...
  7. Study links diet with sleep quality. Sleep Education. http://www.sleepeducation.org/news/2016/02/08/study-links-diet-with-sleep-quality
  8. Changes in back pain, sleep quality, and perceived stress after introduction of new bedding systems. US National Library of Medicine. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697581/
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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Sep 3
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.