Shine a light through your morning fog. A Swedish study suggests that looking at your smart phone can help jolt you awake. People exposed to an hour of blue light (a form of light emitted from phones and tablets) performed faster on a visual test of reaction times than those given 240 milligrams of caffeine the equivalent of two to three cups of coffee. The reason: Exposing your retinas to blue light seems to rouse brain regions that affect alertness and cognitive function. Looking at the screen of your phone or tablet in the morning may have a similar but less intense effect.