You may not realize it, but the strong, toned physique you’re after doesn’t get built in the gym. Muscle growth and repair occurs during the deep stages of sleep, when hormones required for restoration and development are released. You’ve heard of human growth hormone? It’s most abundant while you’re in dreamland.
But if that’s not enough incentive to start getting more sleep, consider these serious sleep stats: Fatigue can cause negative side effects on a metabolic level too, impairing your endurance performance as well as recovery, not to mention increasing your risk of type 2 diabetes.
Research from the University of Chicago Medical School studied the effects of three different durations of sleep in healthy, young males. After only one week of reduced sleep (four hours per night), the participants’ ability to manage glucose levels in their blood slowed by almost 40 percent. This influence on the body’s ability to process glucose is supported by several studies that suggest a correlation between sleeping less than five hours a night and an increased risk of type 2 diabetes.
During the sleep deprivation period, the subjects also experienced elevated levels of the stress hormone cortisol, a catabolic hormone linked to impaired recovery in athletes, as well as memory impairment, age-related insulin resistance and the accumulation of abdominal fat.
At the very least, you can’t give it your all in the gym if you’re exhausted—you may even end up hurting yourself if you’re feeling weak or unfocused. Making an effort to hit the hay a little earlier not only allows your body to properly recover from your last workout, but restores your energy so you can make the next one count too.