Here’s what happens when you don’t get enough sleep: Neurons die, the brain shrinks, and trash piles upPeople who regularly have trouble falling asleep and staying asleep (one study drew the line at 6.8 hours) show changes in brain volume—actual shrinking, in some cases—in regions important for memory and problem solving. “We’ve always presumed that you can take the weekend to catch up and be fine,” says Sigrid Veasey, MD, a University of Pennsylvania researcher, but that may not be the case. When she deprived mice of sleep for 3 days, they lost 25% to 30% of the neurons critical for focused attention—and those remaining were impaired. What’s more, these brain cells never regenerated. Clearly, something important is happening while we slumber, but exactly what sleep accomplishes for the brain has been a mystery. That’s why scientists got excited when researchers at the University of Rochester Medical Center recently offered a new theory. While observing the brains of sleeping mice, they discovered a kind of brain-cleansing system that flushes away neural debris. This “cellular trash” includes beta-amyloids and other proteins—the dreaded buildup of which is associated with Alzheimer’s. The brain sputters today, tomorrow, and well into the futureIn one study, young healthy people whose sleep was limited to 7 hours per night for one week showed impaired brain function that persisted even after 3 nights of recovery rest. Scarier is that with chronic short sleep, you may feel fully rested. When study subjects were restricted to 4 hours of sleep for 5 days, they reported feeling very tired following the first night but they didn’t get any sleepier after that—even though their performance slid significantly. Chronic sleep loss, in effect, blunts perception of impairment. What’s more, a 15,000-person study found that getting an average of less than 5 hours of sleep per night for several years resulted in a decline in memory performance equivalent to the brain aging 2 years. Have we convinced you to turn in early tonight? Excellent. This simple breathing technique can help you get to sleep. MORE: 20 Little Ways To Sleep Better Every Night
