Sleep and Obesity: Mechanisms of Association

Epidemiologic studies demonstrate that both prolonged and reduced sleep duration is associated with increased risk of excessive weight and obesity. The aim of the review was to analyze probable mechanisms of association of sleep duration and obesity elucidated in current scientific literature. Several proposed mechanisms of such an association exist: an imbalance of appetite regulating hormones resulting from decreased sleep duration; fatigue or decreased activity during the daytime, leading to sedentary behavior with decreased energy expenditure; changes in eating behavior with increased daily calorie intake. The article gives a comprehensive review of factors, mediating the association of sleep duration and obesity (age, gender, ethnic origin), studies of neurohormonal regulation of sleep in association with obesity (the influence of sleep duration on thermoregulation, appetite center – increased grelin-to-leptin ratio); the relationship of sleep with growth hormone and insulin-like growth factor-1, with hypothalamic-pituitary-adrenal axis, and non-hormonal factors, stimulating food intake. Data indicating that increased sleep duration is often associated with decreased sleep quality are presented. Besides traditional risk factors – unhealthy diet and decreased physical exercise, specific attention should be given to the problems, associated with sleep disorders to increase the efficacy of treatment and prevention of obesity.