As we go deeper under the hood, sleep becomes even more vital, playing a major role in brain maintenance. While we sleep, the brain is able to get rid of toxins, including proteins that are associated with Alzheimer’s disease. Which is to say, if we don’t allow the brain time to do this crucial work, the cost can be high.

Sleep affects our mental health every bit as profoundly as it does our physical health. Sleep deprivation has been found to have a strong connection with practically every mental health disorder we know of, especially depression and anxiety. “When you find depression, even when you find anxiety, when you scratch the surface 80 to 90 percent of the time you find a sleep problem as well,” says University of Delaware psychologist Brad Wolgast. In the Great British Sleep Survey, researchers found that sleep-deprived people were seven times more likely to experience feelings of helplessness and five times more likely to feel lonely.

Nancy Fox, who runs the healthy-eating website Skinny Kitchen, wrote evocatively about the effects of sleep on her emotional health: “When I was short on sleep it felt like my ‘cup of stress’ was full and the least extra amount made it spill over. I remember sitting in my car in the parking lot of the restaurant and getting a call telling me that it was my day with the carpool, and I had forgotten to pick up the kids. . . . It literally blew me out! . . . The lack of sleep was making me more emotionally fragile . . . [and] making small problems feel like big ones.”

Sleep deprivation also takes a toll on our mental abilities. “Your cognitive performance is reduced greatly,” said Till Roenneberg, a professor at Ludwig-Maximilians University in Munich. “Memory capacity is reduced. Social competence is reduced. Your entire performance is going to suffer. The way you make decisions is changed.”

Fact: when Golden State Warriors player Andre Iguodala improved his sleep habits, his playing time increased by 12 percent and his three-point shot percentage more than doubled. His points per minute went up by 29 percent, and his free-throw percentage increased by 8.9 percent. His turnovers decreased by 37 percent per game, and his fouls dropped by 45 percent.

In just two weeks of getting six hours of sleep per night, the performance drop-off is the same as in someone who has gone twenty-four hours without sleep. For those getting just four hours, the impairment is equivalent to that of going forty-eight hours without sleep. According to a Today show survey, the side effects of not getting enough sleep include difficulty concentrating (29 percent), losing interest in hobbies and leisure activities (19 percent), falling asleep at inappropriate times throughout the day (16 percent), losing your temper or behaving inappropriately with children or partners (16 percent), and behaving inappropriately at work (13 percent).

If a friend described chronic behavior like this to you, you might reasonably worry that he or she was having a drug or alcohol problem and stage an intervention. But we still have a long way to go toward treating sleep deprivation with the same seriousness and urgency.

Excerpted from THE SLEEP REVOLUTION by Arianna Huffington. Copyright © 2016 by Christabella, LLC. Published by Harmony Books, an imprint of Penguin Random House LLC.

Originally published at


  • Arianna Huffington

    Founder & CEO of Thrive Global

    Arianna Huffington is the founder and CEO of Thrive Global, the founder of The Huffington Post, and the author of 15 books, including Thrive and The Sleep Revolution. In 2016, she launched Thrive Global, a leading behavior change tech company with the mission of changing the way we work and live by ending the collective delusion that burnout is the price we must pay for success.

    She has been named to Time Magazine's list of the world’s 100 most influential people and the Forbes Most Powerful Women list. Originally from Greece, she moved to England when she was 16 and graduated from Cambridge University with an M.A. in economics. At 21, she became president of the famed debating society, the Cambridge Union.

    She serves on numerous boards, including Onex, The B Team, JUST Capital, and Gloat.

    Her last two books, Thrive: The Third Metric to Redefining Success and Creating a Life of Well-Being, Wisdom, and Wonder and The Sleep Revolution: Transforming Your Life, One Night At A Time, both became instant international bestsellers. Most recently, she wrote the foreword to Thrive Global's first book Your Time to Thrive: End Burnout, Increase Well-being, and Unlock Your Full Potential with the New Science of Microsteps.