Many studies have linked poor sleep to obesity and other health problems, and now new research suggests a reason why. People chronic insomnia were found to have 30 percent lower nighttime levels of the hormone ghrelin, which is involved in appetite control.
These findings help shed light on why sleep deprivation might encourage weight gain and its related health consequences.
For the study, 14 men with chronic insomnia and 24 healthy men spent two nights in the sleep lab. Researchers used a catheter to periodically take blood samples from the men as they slept, looking for fluctuations in the hormones leptin and ghrelin. Low blood levels of leptin promote hunger, and ghrelin is secreted by the stomach to boost appetite.
The researchers theorized that insomnia patients' ghrelin levels are lower than normal at night, but elevated during the day, boosting their appetites. Another possible explanation is that people with chronic insomnia may have consistently lower levels of ghrelin, pointing to a general dysregulation which affects the expression of the hormone.