Dr. Bob Sugar, of Texas Health Memorial Hospital, says research indicates that red light may help promote sleep by stimulating the production of the hormone melatonin in the body, which helps regulate sleep by sending the body signals when it is time to sleep.
According to experts, the retina contains highly specialized photoreceptors, which are particularly sensitive to blue and white light. Blue light stimulates certain parts of the brain that make us feel more alert, and it also blocks the secretion of the sleep-promoting hormone melatonin.
Hence, exposure to blue light at night can trick our minds into thinking that it is daytime and disrupt our circadian rhythms, which in turn disrupt our sleep.
In contrast, brain cells are less sensitive to warm colors like orange and red, which leads to more melatonin and thus better sleep.