Light Modulates Leptin and Ghrelin in Sleep-Restricted Adults

• Published in: International Journal of Endocrinology Vol. 2012; no. 2012; pp. 547 - 552
• Main Authors: Figueiro, Mariana G., Plitnick, Barbara, Rea, Mark S.
• Format: Journal Article
• Language: English
• Published: Cairo, Egypt Hindawi Limiteds 01-01-2012; Hindawi Puplishing Corporation; Hindawi Publishing Corporation; John Wiley & Sons, Inc; Hindawi Limited
• Subjects: Clinical Study
• ISSN: 1687-8337; 1687-8345
• DOI: 10.1155/2012/530726

Acute and chronic sleep restrictions cause a reduction in leptin and an increase in ghrelin, both of which are associated with hunger. Given that light/dark patterns are closely tied to sleep/wake patterns, we compared, in a within-subjects study, the impact of morning light exposures (60 lux of 633-nm [red], 532-nm [green], or 475-nm [blue] lights) to dim light exposures on leptin and ghrelin concentrations after subjects experienced 5 consecutive days of both an 8-hour (baseline) and a 5-hour sleep-restricted schedule. In morning dim light, 5-hour sleep restriction significantly reduced leptin concentrations compared to the baseline, 8-hour sleep/dim-light condition (t1,32 = 2.9; P=0.007). Compared to the 5-hour sleep/dim-light condition, the red, green, and blue morning light exposures significantly increased leptin concentrations (t1,32 = 5.7; P<0.0001, t1,32 = 3.6; P=0.001, and t1,32 = 3.0; P=0.005, resp.). Morning red light and green light exposures significantly decreased ghrelin concentrations (t1,32 = 3.3; P<0.003 and t1,32 = 2.2; P=0.04, resp.), but morning blue light exposures did not. This study is the first to demonstrate that morning light can modulate leptin and ghrelin concentrations, which could have an impact on reducing hunger that accompanies sleep deprivation.