A new study by Northwestern University Chicago suggests that exposure to blue light before and after the evening meal increases hunger altering metabolism.
For the study, the researchers examined 10 healthy adults with regular sleep and eating schedules. They also received identical carbohydrate-rich isocaloric meals.
The participants had to finish a four-day procedure under dim light conditions that involved exposure to less than 20 lux during 16 hours awake cycle and less than 3 lux during eight hours of sleep.
The third day, the participants were exposed to three hours of 260 lux blue light starting 10.5 hours after they awoke. The researchers compared the effects with dim light exposure.
According to the researchers, blue light exposure was linked to an increase in hunger that began 15 minutes after the light was on and was still present almost two hours after the meal. The exposure to blue light also reduced sleepiness and resulted in higher measures of insulin resistance.
"It was very interesting to observe that a single three-hour exposure to blue-enriched light in the evening acutely impacted hunger and glucose metabolism," said study co-author Ivy Cheung, a doctoral candidate in the Interdepartmental Neuroscience program at Northwestern University in Chicago, Illinois. "These results are important because they suggest that manipulating environmental light exposure for humans may represent a novel approach of influencing food intake patterns and metabolism," he said in a press release.
Cheung stated that further research is required to understand how the blue light affects hunger and metabolism.
The research abstract was published recently in an online supplement of the journal Sleep and will be presented Tuesday, June 3, in Minneapolis, Minnesota, at SLEEP 2014, the 28th annual meeting of the Associated Professional Sleep Societies LLC.
