Examining the Effects of Blue Light on Melatonin, Mood, and Neurobehavioral Performance

Examining the Effects of Blue Light on Melatonin, Mood, and Neurobehavioral Performance

The pineal hormone melatonin can become dysregulated with evening light exposure and changes in sleep/wake behavior. Dysregulated melatonin is associated with impaired mood and cognitive performance. This study examines the effects of modifying short-wavelength (blue) light exposure on evening melatonin levels, sleep disturbances and self-reported mood. To that end, we are testing the effect of blocking blue light during the evening on salivary melatonin, sleep quality, cognitive performance, and mood. Participants undergo one control and one experimental condition involving the use of filtered glasses to attenuate blue wavelength light using a repeated measures, randomized crossover design. The control and experimental condition consists of five days of monitoring using actigraphy watches to non-invasively record sleep patterns, activity level, and light exposure. During the experimental condition participants are instructed to wear a pair of specialized glasses that reduces short wavelength light in the evening. Melatonin levels are quantified from saliva samples. We assess self- reported health through the NIH Toolbox Emotion battery. Neurobehavioral performance is assessed across cognitive domains through a series of tasks on the NIH Cognition Toolbox battery. Preliminary results show an increase in melatonin levels as well as an increase in self reported overall life satisfaction and a decrease in fear, sadness and anger after just five days of evening blue light suppression. The use of light altering glasses will show how this intervention can potentially be applied to at risk populations (e.g. shift-workers or students who spend nighttime hours studying with electronic devices) in order to lessen the deleterious effects of light exposure at night.