Early morning blue light is useful for circadian rhythm

Blue light exposure therapy with early morning sessions can help people with mild traumatic brain injury and generally to regulate the circadian rhythm. A team of researchers led by William D. “Scott” Killgore who published their study on Neurobiology of Disease is of this opinion.

According to the researchers, a short exposure, held every morning, to the wavelength of blue light can be of help especially for the circadian rhythm and this consequently also helps with the quality and regularity of sleep. The researchers realized that these short therapy sessions could be particularly useful for people with mild traumatic brain injuries because the improvement in sleep went in parallel with an improvement in cognitive functions due also to a decrease in daytime sleepiness and in general thanks to an effective repair of the brain, as explained by Killgore himself who is professor of psychiatry at the College of Medicine of the University of Arizona.

Brain lesions can lead to an explosion of pressure in the brain and this can cause microscopic damage to blood vessels and brain tissue, as Killgore himself explains: “Your brain has the consistency of a large Jell-O. Imagine a bowl of Jell-O gets punched or slammed into the steering wheel in a car accident. What are you doing? He absorbs the shock and bounces back. During that impact, microscopic brain cells thinner than a lock of hair can easily stretch and tear due to force.”

Supported by previous research showing that the brain can repair itself during sleep, Killgore and his colleagues tried to figure out whether a better sleep could actually lead to faster recovery. In a randomized clinical trial, they exposed several patients to a blue light projected from a desk device. This happened for 30 minutes every morning for six weeks.

For the control group, which was exposed to bright amber light, those exposed to blue light showed suppression of melatonin in the brain, helping people to align with their natural circadian rhythm and sleep-wake cycle.

“When you are exposed to blue light in the morning, move your brain’s biological clock so that your melatonin will kick in at night. First and it helps you fall asleep and sleep,” Killgore explains again. People exposed to the blue light not only showed more regular sleep, they also showed less drowsiness during the day.

The results of such a study can be explained by the fact that humans have mostly evolved over millions of years with a regular 24-hour light-dark cycle and an almost total lack of artificial lights (except for the dim light of a fire). This has led to a circadian rhythm deeply rooted in all our cells: if we can get cells to follow this archaic circadian rhythm, we can sleep more regularly and much better “because the body and brain can coordinate all these repair processes more effectively,” as the researchers explain.