The American Heart Association has issued its yearly reminder that incidents of heart disease and stroke go up at daylight saving time — a biological "clock shock" thus far unexplained. Changing the clock changes up our body's production of hormones, including melatonin, the night-time hormone that affects sleep; cortisol, the stress hormone; and serotonin, the "feel-good" hormone that helps keep depression and anxiety at bay. It's especially important over the next few days to try to go to bed and wake up at the same time every day, even, as difficult as it is to hear, on weekends. Bhat says...