It’s estimated that 70 million American adults suffer from some kind of sleep disorder. This is troubling because humans need sleep to survive. In fact, almost all animals do. In a 1989 University of Chicago study, rats that were fed and treated well in every way, but deprived of sleep, died after 11 days. There was nothing anatomically wrong with them. Sleep gives the body a chance to rest, recover, and rejuvenate. Sleep disturbances that rob the body of proper sleep lead to a cascade of negative health consequences. About 80% of Americans also fail to get the recommended amount of exercise. Partly as a consequence, roughly two-thirds of us are overweight or obese. You may be thinking, why did he just change the subject? But sleep, exercise, and fitness are interconnected. Each affects the others.

Fitness and Exercise Affect Sleep

People sleep significantly better and feel more alert during the day if they get at least 150 minutes of exercise a week – or 30 minutes, five days a week. In addition, being overweight contributes to sleep disturbances such as apnea. With sleep apnea, a person stops breathing either partially or completely many times throughout the night. That can result in daytime sleepiness or fatigue that often reduces the quality of life and inability to function throughout the day. Too little sleep has been linked to everything from memory loss and other serious cognitive issues to an increased risk for osteoporosis and cancer. Physical activity affects other aspects of life as well. Even controlling for other health factors, people who exercise are 65% less likely to feel sleepy during the day. They are 45% less likely to have trouble concentrating.


Sleep, In Turn, Affects Fitness

The reverse is true too. The benefits of exercise can be undone by insufficient or interrupted sleep.  Research published in the Annals of Internal Medicine found that people who dieted and slept more than seven hours nightly lost twice as much body fat as those on the same diet who slept less than seven hours nightly. Sleep deprivation beyond a single night can begin to affect bodily functions. After four days of insufficient sleep, the body’s ability to use insulin declines 30%. When insulin use malfunctions, the body begins storing fat. It can also lead to diseases, most notably diabetes. Sleeping less than six hours also triggers your brain to crave more food, even when your body is adequately nourished. That leads to over-eating and more weight gain and fat storage. The bottom line is this: we need to sleep in order to exercise and maintain a healthy weight. And we need to exercise and maintain a healthy weight in order to sleep well. It’s a vicious cycle. Or a virtuous cycle, when we make it work in our favor. I talk to patients every day who complain of a laundry list of seemingly disconnected symptoms, such as headaches, fatigue, and acid reflux. I often ask them how they are sleeping. They are surprised to discover that improving their sleep can bring immediate relief to many of their symptoms and provide them with the energy to address other issues – such as their need for more physical activity – that then improve their ability to sleep.