The Stunning Consequences of Not Getting Enough Sleep


Many people don’t get as much sleep as they should. And their brains are paying the price.

April 1, 2009

By Allison Ford

Nothing feels worse than hearing your alarm clock ring in the morning when your body is screaming for a few extra hours of rest. Given the opportunity, who wouldn’t get more sleep? If I had a choice between a year of unlimited Easter candy and a year of unlimited sleep, I’d say “Bye-bye Cadbury” and “Hello, bed!”

Many people don’t get as much sleep as they should. Since the invention of the light bulb, people sleep about 500 hours per year less than they used to. Whether we’re kept awake by our partner’s snoring or we stay up too late watching TV, we wake up tired, groggy, and cranky. No wonder the coffee industry does so well. Unfortunately, sleep deprivation has some side effects and they can’t all be remedied with a little extra caffeine.

This Is Your Brain on Sleep

While the mechanism of sleep isn’t fully understood yet, doctors and scientists do know that it’s one of our body’s most important processes. Studies show that sleep is important for cellular renewal, helping to replace muscle tissue and dead cells throughout the body. Studies have also shown that sleep is a key time for the brain to process and archive information, including memories. Deep, restorative REM sleep, the kind associated with dreaming, seems to stimulate regions of the brain used in learning.

Every night without adequate rest is like adding to a sleep debt—eventually it will have to be repaid. Even after one sleepless night, we can feel the first effects of sleep deprivation—irritability, memory loss, and drowsiness. Continued sleep deprivation can result in trouble concentrating, blurry vision, impaired judgment, and even more severe mental effects. After just a few days without any sleep, people can begin to experience hallucinations, mania, and nausea. Luckily, if you repay your sleep debt right away, those effects vanish immediately.

Short-Term Side Effects

Sleep deprivation doesn’t just cause mental deficits; our physical abilities are diminished too. Studies have demonstrated that not sleeping can reduce glucose metabolism by as much as 40 percent. We use stored glucose for energy and sleep deprivation can interfere with how the body stores and processes it. Sleep-deprived athletes also experience high levels of cortisol, a stress hormone, as well as lower levels of human growth hormone, which is important for muscle repair. The immune system is also thought to be maintained while asleep; people who don’t get enough sleep tend to be more susceptible to infections and have slower healing times.

Sleep deprivation also has an effect on how the brain stores information. A study at the University of Pennsylvania showed that mice who were taught a task and allowed to sleep afterward remembered what they had learned better than mice that didn’t sleep. Among school-aged children, those who get even one less hour of sleep than their peers have shown to perform more poorly on tests of memory and attention.

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