Five Things About Daylight Saving Time

1. A Founding Father was an early advocate. In 1784 Benjamin Franklin observed that during summer months, people slept during the daylight hours of morning and then burned candles at night for illumination. Thus adjusting schedules to begin earlier in the day during summer months would substitute free sunlight for costly wax. Though Franklin advocated changing schedules, he did not propose changing the clock. This idea was first suggested in Britain in 1907, and it was implemented in warring nations in 1916 as an energy-saving measure.

2. Farmers were not. The notion that farmers pushed for daylight saving time to give them more time in the field is a myth. In fact, farmers consistently came out against a peacetime daylight saving time, which was not implemented in the U.S. until 1966. Losing an hour of morning light meant an early rush to get crops to market. And dairy farmers noted that cows respond poorly to changes in their schedule.

3. The health effects of DST are a mixed bag. More time spent pursuing outdoor activities and increased exposure to vitamin D can be beneficial. However, studies have found increases in such maladies as workplace accidents, heart attacks, headaches and even suicides at the start and end of daylight saving time, attributable to the negative effects of disrupted sleep rhythms. This is particularly so for people with mental health problems.

4. It’s good for business—except when it’s not. Outdoor sports facilities (think golf courses), the grill and charcoal industries and retail groups have long argued that DST is good for business—and for theirs, it is. Less fortunate: airlines that have to scramble to keep international flights running smoothly during the time changes, and television networks that lose prime-time viewers to the extended daylight.

5. The biggest argument for DST is questionable. The idea that daylight saving time saves energy has been the most formidable argument for its implementation and extension. Most recently, the U.S. Energy Policy Act of 2005 extended DST in 2007 by three weeks in the spring and one week in the fall. But studies by economists in 2008 and 2011 suggest that DST leads to the same amount of electricity use, but shifts it to different parts of the day, or even increases energy use slightly if people engage in additional energy-intensive activities (examples: driving and using air-conditioning).

Daniel Phaneuf is a CALS professor of agricultural and applied economics.