How Hormones Affect Your Sleep
“Leptin and ghrelin work in a kind of “checks and balances” system to control feelings of hunger and fullness, explains Michael Breus, PhD, a faculty member of the Atlanta School of Sleep Medicine and director of The Sleep Disorders Centers of Southeastern Lung Care in Atlanta. Ghrelin, which is produced in the gastrointestinal tract, stimulates appetite, while leptin, produced in fat cells, sends a signal to the brain when you are full.
So what’s the connection to sleep? “When you don’t get enough sleep, it drives leptin levels down, which means you don’t feel as satisfied after you eat. Lack of sleep also causes ghrelin levels to rise, which means your appetite is stimulated, so you want more food,” Breus tells WebMD. The two combined, he says, can set the stage for overeating, which in turn may lead to weight gain.
Studies: Those Who Sleep Less Often Weigh More
How the hormones leptin and ghrelin set the stage for overeating was recently explored in two studies conducted at the University of Chicago in Illinois and at Stanford University in California.
In the Chicago study, doctors measured levels of leptin and ghrelin in 12 healthy men. They also noted their hunger and appetite levels. Soon after, the men were subjected to two days of sleep deprivation followed by two days of extended sleep. During this time doctors continued to monitor hormone levels, appetite, and activity.
The end result: When sleep was restricted, leptin levels went down and ghrelin levels went up. Not surprisingly, the men’s appetite also increased proportionally. Their desire for high carbohydrate, calorie-dense foods increased by a whopping 45%.
It was in the Stanford study, however, that the more provocative meaning of the leptin-ghrelin effect came to light. In this research — a joint project between Stanford and the University of Wisconsin — about 1,000 volunteers reported the number of hours they slept each night. Doctors then measured their levels of ghrelin and leptin, as well as charted their weight.
The result: Those who slept less than eight hours a night not only had lower levels of leptin and higher levels of ghrelin, but they also had a higher level of body fat. What’s more, that level of body fat seemed to correlate with their sleep patterns. Specifically, those who slept the fewest hours per night weighed the most.” - WebMD