Do all sedentary activities lead to weight gain: sleep does not.

PURPOSE OF REVIEW: To discuss the benefits of having a good night's sleep for body weight stability. RECENT
FINDINGS: Experimental studies have shown that short-term partial sleep restriction decreases glucose tolerance, increases sympathetic tone, elevates cortisol concentrations, decreases the satiety hormone leptin, increases the appetite-stimulating hormone ghrelin, and increases hunger and appetite. Short sleep duration might increase the risk of becoming obese, because it does not allow the recovery of a hormonal profile facilitating appetite control. Lack of sleep could also lead to weight gain and obesity by increasing the time available for eating and by making the maintenance of a healthy lifestyle more difficult. Furthermore, the increased fatigue and tiredness associated with sleeping too little could lessen one's resolve to follow exercise regimens.
SUMMARY: Short sleep duration appears to be a novel and independent risk factor for obesity. With the growing prevalence of chronic sleep restriction, any causal association between reduced sleep and obesity would have substantial importance from a public health standpoint. Future research is needed to determine whether sleep extension in sleep-deprived obese individuals will influence appetite control and/or reduce the amount of body fat.