A team of researchers at the Korea Advanced Institute of Science and Technology (KAIST; Daejon, South Korea) has shown that blue-enriched LED light can effectively help people overcome morning drowsiness. The study could provide the basis for major changes in future lighting strategies and thereby help create better indoor environments.
Initial studies on light sources have shown that blue monochromatic, fully saturated lights are effective for stimulating physiological responses, but the relative effectiveness of commercially available white light sources is less well understood. Moreover, the research was more focused on the negative effects of blue light—for instance, when people are exposed to blue light at night, they have trouble achieving deep sleep because the light restrains melatonin secretion.
However, Hyeon-Jeong Suk and Kyungah Choi, who are professors in the Department of Industrial Design at KAIST, and their team argue that the effects of blue-enriched morning light on physiological responses are time-dependent, and that it has positive effects on melatonin levels and the subjective perception of alertness, mood, and visual comfort compared with warm white light.
The team conducted an experiment with 15 university students. They investigated whether an hour of morning light exposure with different chromaticity would affect their physiological and subjective responses differently. The decline of melatonin levels was significantly greater after the exposure to blue-enriched white light in comparison with warm white light.
"Light takes a huge part of our lives since we spend most of our time indoors," Suk explains. "Light is one of the most powerful tools to affect changes in how we perceive and experience the environment around us."
"When we investigate all of the psychological and physiological effects of light, we see there is much more to light than just efficient quantities," Choi adds. "I believe that human-centric lighting strategies could be applied to a variety of environments, including residential areas, learning environments, and working spaces to improve our everyday lives."
Full details of the work appear in the journal Scientific Reports.