Daylight Saving Time has mixed effects on people’s health. Transitions into and out of DST can disturb people’s sleeping patterns, for example, and make them more restless at night. Night owls tend to be more bothered by the time changes than people who like mornings.
There’s a spike in heart attacks during the first week of Daylight Saving Time, according to a study published in 2008. The loss of an hour’s sleep may make people more susceptible to an attack. When Daylight Saving Time ends in the fall, heart attacks briefly become less frequent than usual.
People are safer drivers during daylight hours, and researchers have found that Daylight Saving Time reduces lethal car crashes and pedestrian strikes. In fact, a study concluded that observing Daylight Saving Time year-round would annually prevent about 195 deaths of motor vehicle occupants and about 171 pedestrian fatalities.
The Energy Policy Act of 2005, signed into law by President George W. Bush, extended the length of Daylight Saving Time by four weeks. It now begins at 2 AM on the second Sunday in March. It ends on the first Sunday in November.
Also in 2005, Kazakhstan abolished Daylight Saving Time, citing negative health effects. The country’s government reportedly calculated that 51.6 percent of Kazakhs responded badly to the time change.
Two states — Arizona and Hawaii — and four U.S. territories — American Samoa, Guam, Puerto Rico, and the U.S. Virgin Islands — don’t observe Daylight Saving Time. Indiana adopted Daylight Saving Time in 2006.
Daylight Saving Time was first used during World War I, as part of an effort in the United States and other warring countries to conserve fuel. In theory, using daylight more efficiently saves fuel and energy because it reduces the nation’s need for artificial light.
The first American to advocate for daylight saving was Benjamin Franklin. He realized in 1784 that many people burned candles at night yet slept past dawn in the summer, wasting early-morning sunlight.