Light affects visual as well as non-visual pathways in ways that are not fully understood. The suppression of melatonin by light at night may mediate the positive effects of light on nocturnal performance and alertness. Recent work by our laboratory suggests that long-wavelength (red) light, which does not suppress melatonin, positively impacts objective and subjective alertness and certain types of performance both at night and during the daytime. Initially, the alerting effects of light were observed during the nighttime and after exposure to higher levels (>1000 lux at the cornea) of white light or lower (40 lux at the cornea) levels of short-wavelength (blue) light. It was suggested, based on these earlier studies, that the observed alerting effects of light were mediated by light~s ability to cease nocturnal melatonin production. Melatonin is ahormone produced at night and under conditions of darkness. It is known as a ~darkness hormone~ because it is always produced during the biological night, and in diurnal species it signals it is time to sleep. However, recent studies by our laboratory showed a strong alertingeffect of long-wavelength (red) light, as measured by electroencephalogram (EEG), as well as self-reports of sleepiness during the daytime (when melatonin levels are low) and at night (when melatonin levels are high). Red light also reduced reaction times in certain types ofperformance tests. Therefore, light can have an impact on alertness and certain types of performance without affecting areas in the brain that are not associated with acute melatonin suppression.
|Effective start/end date||28/07/16 → 28/07/16|
- Office of Naval Research: $149,275.00