Does blue light keep you awake?

A new study says that exposure to shortwave light, which appears blue, immediately improves alertness and performance. Researchers at Brigham and Women's Hospital and Harvard Medical School compared the effects of blue light and green light on volunteers during the night. read more

Despite all these efforts, some studies suggest that simply staring at a screen before bed, whether it's giving off blue light or not, can keep you awake longer. Bright light in our environment can signal our brains to stay alert and we get a direct dose of it by looking at a phone or computer. read more

However, light — particularly of the blue variety — can keep the pineal gland from releasing melatonin, thus warding off sleepiness. You don’t have to be staring directly at a television or computer screen: If enough blue light hits the eye, the gland can stop releasing melatonin. read more