Sitting up late at night with TV, computer, and phone screens in our face can wreak havoc on our sleep. "Light is very important for sleep and is really the dominant cue that helps in training our circadian system, which regulates sleep and wake," says Dautovich. Our bodies are designed to be up and active when it's light and resting when it's dark. That also means that we're programmed to start waking up when the sun rises. For that reason, alarms that gradually get brighter as it gets closer to our wake up time may work well for some people. Philip's Wake-Up Light ($100) is a favorite among proponents of progression light clocks.