Morning Bright Light Exposure Improves Sleep and Alertness
The relationship between morning light and sleep has not been well documented. People who work or spend most of their time indoors have less access to morning bright daylight. A new study investigated whether exposure to 1.5 hours of morning bright electric light using a lightbox (comparable to a sunrise or sunset) vs. regular indoor light in the early morning for one week would benefit sleep among individuals who spent most of their time indoors during the day. The results showed that exposure to morning bright light versus regular indoor light yielded shorter sleep-onset latencies (i.e. individuals fell asleep faster), a higher sleep efficiency (greater time asleep vs. time in bed), less sleep fragmentation, and increased morning alertness. These findings suggest that morning exposure to bright light such as sunlight enhances sleep and alertness compared to regular indoor light.