Leptin Is Connected with Sleep

How long an individual sleeps is associatedwith human leptin levels, accordingto the results of a study reported in theNovember 2004 issue of the Journal ofClinical Endocrinology & Metabolism.Leptin is a hormone that plays a part inbalancing signals for calorie intake withenergy expenditure, possibly making individualsbelieve that they need to consumemore and potentially leading toweight gain.

The study involved 11 healthy 22-yearoldmen who spent 16 consecutive nightsin a sleep laboratory. The 16 nightsincluded 3 nights with an 8-hour bed time,6 nights with a 4-hour bed time, and 7nights with a 12-hour bed time. Theresults of the study indicated that, whensleep was restricted from 12-hour bedtimes to 4-hour bed times, maximum leptinlevels were 26% lower.