The practice of changing the local time so that peak periods of activity coincide with daylight is widely attributed to Benjamin Franklin, who, perhaps satirically, suggested a time change in 1784 for economic reasons—to cut back on candle burning in the evenings.
European countries first adopted daylight saving time (DST) during World War I to conserve energy. The United States soon followed suit but ended the practice after the war.
In 1966, Congress mandated a one-hour advance on the last Sunday in April—since then it has moved to the second Sunday in March—and an hour retreat on the last Sunday in October (since moved to the first Sunday in November) to conserve energy, extend recreational hours into the evening, and promote tourism. (It’s rumored that the golf industry and candy makers—proponents of extending the end date to occur after Halloween—were among those who successfully lobbied Congress to institute DST.) Some states and territories have chosen not to participate in DST, including Hawaii, most of Arizona, Puerto Rico, and Guam.
This article first appeared in the April 2020 issue of UC Berkeley Health After 50.