A simple Google search about sleep these days will reveal article upon article about the lack of sleep sweeping the country. The CDC released a study this year that shows more than 1/3 of American adults are not getting enough sleep on a regular basis. The recommended 7-9 hours of sleep are needed for good health, safety, and optimum performance, according to the National Sleep Foundation. In fact, over the past 40 years, Americans have cut their sleep time by 1-2 hours a night. These trends towards more stress and less sleep coincide with Americans becoming heavier each year. It is no surprise then that recent research has found that both stress and sleep are correlated with weight gain.
Lack of sleep appears to affect hormone levels. Leptin is a hormone released by fat cells which signals the brain to stop eating. Ghrelin, a hormone made in the stomach, signals the body to continue eating. Studies have shown that in individuals who are sleep deprived, leptin levels are lower and ghrelin levels are higher. This combination is therefore likely to increase appetite. On top of all that, the brain interprets a drop in leptin as a sign of starvation. In order to protect itself, the body not only responds by increasing your appetite, but it also burns fewer calories.
But, that’s not all. Lack of sleep also seems to affect insulin resistance and blood glucose levels. Insulin is the hormone that lets glucose (aka blood sugar) into the body’s cells, to be burned for energy. When people are insulin resistant, the insulin does not work efficiently. This can increase the risk for heart attack, stroke, and diabetes.
As with lack of sleep, being stressed also affects certain hormones. When the body is stressed, it releases adrenaline, along with corticotrophin releasing hormone (CRH) and cortisol. The adrenaline and CRH first affect the body by decreasing your appetite, since in the typical “fight or flight response” (when stress is highest), having to stop and eat would surely not help to save your life. However, this decreased appetite only lasts for a short time. Cortisol kicks in later. Its job is to help the body replenish its stores when the stress has passed, and cortisol’s effects last a lot longer. Moreover, since the body is looking to quickly replenish its energy stores, it begins to crave sugar. Cortisol may also work to slow down your metabolism, since it is trying to quickly replenish lost nutritional stores.
Stress may also affect weight gain in other ways. Aside from cortisol’s affect on the body, stress often leads to nervous energy. An increase in nervous energy in some people leads to nervous or emotional eating. Furthermore, stress is also largely associated with a lack of time. This lack of time may affect being able to prepare healthy meals, leading to an increase in fast food consumption, less time to exercise, or to a lack of sleep, thus starting a vicious cycle…
What to do?