Why Good Sleep Can Improve Your Fitness Levels

by Natalie Belford

So you’ve been working out to the best exercise videos but still don’t see much results. You even try to eat the right foods and go on a diet. But you seem to have reached a plateau. What’s stopping you from getting leaner? Maybe it’s the amount of sleep you get. The lack of sleep can make you fat. Remember, cortisol is one of the hormones that stimulates fat storage and revs up your appetite to make sure you have energy for all the stressful challenges that you face. When you are sleep deprived, however, your body interprets this as a stressor—after all, it takes a lot of extra energy to go without sleep—so your cortisol levels remain elevated, and so does your appetite for carbohydrates.

Other kinds of hormonal problems can be triggered by lack of sleep. For example, a study at the University of Chicago found that young adults who were sleep deprived showed a significant loss in their ability to process glucose (blood sugar), which caused their bodies to produce more insulin.

Insulin is the key hormone that controls our blood sugar levels after we consume carbohydrates. Insulin metabolizes blood sugar so that muscle tissue can use it for fuel. It also helps store excess blood sugar in the liver and tissues as glycogen, or in our bodies as fat. So excess production of insulin can result in too much blood sugar being stored as fat, interfering with weight loss efforts.

This is why a diet of lean protein, low-glycemic carbohydrates, and “good” omega-3s and omega-6s is so important. It helps keeps our insulin levels low. Fat-deprived people eating too many carbohydrates — even complex carbohydrates—program their insulin levels to remain high. The insulin, in turn, instructs their bodies to store fat. Excess insulin also triggers a whole host of symptoms, including irritability, difficulties with memory and concentration, and food cravings. Too much insulin production can also exhaust the islet of Langerhans—the part of your pancreas that produces insulin—which can put you at risk for diabetes.

Levels of the hormone leptin also drop when you don’t get enough sleep. Leptin helps regulate carbohydrate metabolism, so lack of sleep can boost your carb cravings. You also need deep sleep to produce growth hormone, which helps give you supple skin.

Growth hormone also causes your body to burn fat in order to repair the tiny tears in your muscles caused by exercise. This gives your body a higher muscle to fat ratio, which boosts your metabolism, helping you to lose weight and keep it off.

Growth hormone is released while you sleep, raising gradually from about 10 p.m., and peaking at about 2 a.m. Eating a light, low-carb “friendly” snack—a fruit smoothie or a deviled egg—just before you retire can boost growth hormone production even more.

So remember, sleeping is vital not just for strength training but a healthy metabolism and weight loss!