If you've spent the day outdoors, the brightness of the phone makes no impact, Zeitzer says. It's what you're doing on that phone that matters. "At that point, it's not the blue light keeping you up.

The theory is that the blue light radiating off your phone will signal ... taking in sunlight between 10,000 lux on a cloudy ...

A study suggests that wrapping a surfboard in very bright lights — like aquatic Christmas trees — could make the surfer less ...