Visor Light Program for Circadian Phase Shiftin

Timed exposure to bright light for resetting human circadian rhythms makes it possible to minimize the effects of jet lag, and improve the safety and effectiveness of military and civilian traelers. This project will test the efficacy of a promising bright light program using the head-mounted Light Visor. The Visor is easily carried along during long-distance flights, and affords the user many advantages and considerably more mobility over bright-light room and light boxes that have been tested thus far. Phase I work consists of a laboratory simulation of jet lag in human volunteers subjected to an 8-hr sleep-wake schedule phase advance equivalent to eastward travel across 8 time zones. The study will evaluate the rates of re-entrainment of circadian rhythms following exposure to broght whiet Visor light vs circadian measures following exposure to dim red Visor light -- the latter used a a bilogically inactive placebo. Phase shift marker data will include core body temperature, sleep patterns, plasma cortisol and melatonin levels, and performance and alertness tests. When validated for treating jet lag, the Visor program will offer a practical, effective, and reliable means for reducing problems in alterness and performance experienced by global travelers.