The new consumer-oriented bulbs, for example, are designed to regulate the body’s basic need to rest and wake up by stimulating receptors in the eyes that signal to the brain when it is time for bed and when it is time to go about the activities of the day.
When exposed to short-wavelength light, the blue end of the spectrum, those receptors suppress the release of the sleep-inducing hormone melatonin.
Since white artificial light, especially the LEDs used in bulbs and illuminated screens, is typically high in blue, exposure after dusk tends to reduce sleepiness and increase alertness, leading to an epidemic in sleep deficiency, said Dr. Charles A. Czeisler, chief of the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital in Boston and a professor of sleep medicine at Harvard Medical School.
This stuff isn’t particularly “new” in the scientific literature, but it’s become increasingly present in the public consciousness recently. Looking at light intensity and color is simple low-hanging fruit when addressing sleep issues. (Apps like f.lux and blue-blocking glasses are also proactive solutions that don’t involve expensive house-wide lightbulb replacement.)