Daylight Saving Change Bad for Health

Daylight Savings

The clocks move ahead one hour at 2 a.m. on Sunday, March 9, in most of the United States. The annual spring forward ritual will often mean less sleep for most. It can also lead to physical problems. As shown in numerous studies, the change to daylight savings time can be bad for people’s heart health and performance (whether in school, at the wheel or at work).

The physical problems associated with daylight saving time do not take place on the Sunday when the change occurs. They usually show up on the first Monday, when people have to get up earlier for work or school and really notice the difference in sleep and light outside.

The risk of having a heart attack is 10 percent greater on the Monday and Tuesday after the clock is moved forward than other days, according to the University of Alabama at Birmingham. The converse is true in the fall; when clocks move back an hour, the risk of having a heart attack decreases by 10 percent. A study by scientists at the Karolinska Institutet medical university in Stockholm, Sweden, also reported a difference in the likelihood of having a heart attack at the start and the end of daylight saving. However, they only showed a 5 percent difference in the risk at either time of year. That may seem like a small amount. However, as one Swedish researcher noted in Science Daily, approximately 1.5 billion people reside in areas that make daylight savings clock changes every year, so even a 5 percent increase can be bad for a lot of people’s health.

The reason for the impact on hearts is unknown. One theory is that body cells have their own internal “clock” that gets thrown off by the change but adjusts in a few days. The effect is similar to jet lag.

Sleep deprivation at the start of daylight saving time has a negative effect on school and job performance. According to a Sleep Medicine 2009 study, it can take adolescents up to three weeks to adjust their concentration levels back to normal in the classroom after the time change. At work sites, there is more “cyberloafing” done after daylight savings starts. The Journal of Applied Psychology reported in 2012 more workers going to Web sites that were not work-related on the Monday after the spring clock change than other Mondays studied. Clearly, their level of concentration is impacted, too.

Are the spring daylight saving time physical results all bad? No, the added hour of daylight in the evening shows a positive improvement in two areas: traffic accidents and physical activity. Some studies have shown that traffic accidents decrease during daylight savings. This is because fewer accidents take place in daylight hours that in the dark. During daylight savings time, many workers are driving home while it is light that would normally drive home in the dark during standard time. The added daylight has the same impact on physical activity with more people taking walks, riding bikes or doing other physical activity once they come home.

Come Monday, if it is hard getting up for work at the new daylight savingstime, take a deep breath, relax and do not let the change become a bad health problem. Know that at the end of the day, the sun will be shining and there are more daylight hours to enjoy until fall.

By Dyanne Weiss

National Geographic
Los Angeles Times
Science Daily
Science Daily

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