12 Surprising Effects of Daylight Saving Time

March 11, 2019

On Sunday, March 10, clocks across much of the United States “sprang forward” in an effort to end daylight saving time (DST). With that in mind, Mental Floss compiled a list of some unexpected effects of the time change, which you may experienced on “Sleepy Monday.” Here they are:

Increased spending. In 2016 JP Morgan Chase found that DST was "associated with a 0.9 percent increase in daily card spending per capita in Los Angeles at the beginning of DST." 

A higher risk of heart attacks. One study showed a 24 percent increase in the number of heart attacks on the Monday after DST at a group of Michigan hospitals. 

Missed appointments. A 2017 study found that the percentage of missed medical appointments increased significantly following DST. 

More car accidents. A 2001 American study found that there was a significant increase in accidents on the Monday after the shift to DST. A 2018 New Zealand study echoed the sentiment. 

Longer prison sentences. One study found that on "Sleepy Monday," judges handed out five percent longer sentences.

More mining injuries. According to one study of mining injuries from 1983 to 2006, the Monday directly after the switch to DST was associated with 5.7 percent more workplace injuries and 68 percent more workdays lost because of injuries. 

Fewer koala collisions. Because koalas are largely nocturnal, they often cross the road in the evening or at night. By shifting traffic patterns to times when it wasn't dark, the researchers found that DST could "decrease collisions with koalas by 8 percent on weekdays and 11 percent at weekends.”

Decreased satisfaction with life in general. In both the U.K. and Germany, studies have shown that life satisfaction deteriorates in the first week after the switch to DST in the spring.

Sleepier kids. A study published by Sleep Medicine in 2009 found that after the DST transition, the group of school children was sleepier for three weeks after the transition. 

More cyber loafing on the job. A study found that on the Monday after the switch, people searched for 3.1 percent more entertainment websites than the Monday before DST, and 6.4 percent more than the subsequent Monday. 

Mistimed insulin shots. Because most commercial pumps aren't GPS-enabled and lack internal time change mechanisms, they have to be manually set up. 

Higher energy bills. A study ultimately concluded that while DST does save electricity in lighting, this is more than offset by increased demands for heating and cooling.