It’s that time of year again, when we reset our clocks and try to readjust to the time change associated with Daylight Saving Time (DST). Some of us breeze through the change seamlessly, yet others feel out of sorts for days. If you have trouble dealing with this sudden disruption in your routine, it is for good reason.
Even though your brain knows that the time on the clock has changed, your body's internal clock does not. In the fall, when you’ve gained an hour of sleep, you might not feel tired, but you may get cranky when you have to wait an extra hour before your lunch break or when it feels like work should have ended an hour ago. When the clocks move forward in the spring, you'll be robbed of an hour of sleep. That night, you may not be able to fall into your normal sleep rhythms an hour earlier than you’re used to, and you won’t get as much quality sleep as you need.
Since its inception in the early 1900s, DST has been the subject of controversy. Studies are contradictory, showing that DST has both positive and negative impacts on health, safety, energy consumption, and the economy. A sampling of the issues includes:
Health: DST provides more daylight for outdoor exercise and yard work in the evenings, which could improve fitness levels. It also provides more opportunities for sun exposure, which triggers vitamin D synthesis in the skin. However, more sun exposure could lead to higher rates of skin cancer, according to some experts. And some new research shows that heart attacks increase the days following the spring time change (when we lose an hour), but decrease after the fall time change (when we gain an hour).
Safety: In the weeks following the spring time change, there are more traffic accidents. But overall, during the course of DST there are fewer traffic fatalities than during standard time.
Energy Consumption: While it had been hypothesized that DST would help to conserve energy, several studies have shown that DST leads to increased energy and fuel consumption.
Economy: Some industries, like retail businesses and golf courses, benefit from DST, as consumers have more time to shop and play. But other industries including farming, theaters, and prime time television suffer.