Viewing bright light increases alertness, while dim/dark settings increase sleepiness.

“the most powerful driver of your alertness & sleepiness is light.”

“Not surprising given the role of bright light and short wavelength light in particular for creating alertness.”

“First of all, in the first part of your day, that zero to nine hours after waking, you want bright lights, especially overhead lights, as bright as you can keep them without feeling uncomfortable, or certainly not without feeling any pain in your eyes or elsewhere in your body. Bright lights will make for the maximum state of alertness.”

“First of all, in the first part of your day, that 0 to nine hours after waking, you want bright lights, especially overhead lights, as bright as you can keep them without feeling uncomfortable or certainly not without feeling any pain in your eyes or elsewhere in your body. Bright lights will make for the maximum state of alertness.”