Sleep Time and Obesity Risk
Studies that examine levels of ghrelin and leptin after sleep deprivation showed that there was a strong link between appetite regulation and sleep curtailment. Participants in different studies after five nights of normal sleep were subjected to 2 nights of restricted sleep. Researchers found that leptin level reduced when sleep was deprived. Also, hormones that control hunger increased. Ghrelin is among these hormones that increased.
A study which involved 1024 participants was conducted in 2004 to investigate sleep disorders. Polysomnography was conducted for one night, and the participants set their wake and sleep times. They completed questionnaires on their sleeping habits. After the night, serum ghrelin and leptin were evaluated as well as glucose, adiponectin and insulin levels.
When changes were made in the age, sex and BMI, researchers found that when the sleeping hours was reduced from eight to five hours, there was 15.5% decrease in leptin and ghrelin increased by 14.9%. Researchers also found that those who sleep for less than 7.7 hours had increased risk for BMI.