When daylight saving time ends, we set our clocks back one hour, which means we gain an hour of sleep. This usually happens on the first Sunday of November in the United States. As we head into the colder months, there is less daylight, and the sun rises and sets earlier. The end of daylight saving time can have some effects on our health. For example, during the first two days after the time change, the overall rate of ischemic stroke goes up by 8 percent, and this risk is particularly high for people over age 65, whose risk of stroke goes up by 20 percent. However, the rates return to normal after two days. On the other hand, the risk of having a heart attack goes down when the time change ends in the fall, possibly because people get an additional hour of sleep.