How Daylight Saving Time Affects Your Health, According to Science

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On March 10, at 2 a.m. local time, we will turn the clocks forward one hour to 3 a.m. There will be more light in the evening — great for recreational purpose. And there will be less in the morning — not so great for a person’s health because of the sudden shock to the body’s circadian rhythm.

Standard time will on March 10 move to daylight saving time (DST), or summer time, as it is known outside the United States. The change forward, applied in the spring, and back, applied in the fall, is intended to make better use of sunlight and therefore save on energy spending. While moving the clock forward has been the law of the land for decades, why it’s still being used has become a public debate. As its economic effects today are disputed, its negative health risks have been established for years.

It has become so contested that Arizona (except the Navajo region), Hawaii, and the overseas territories of the United States don’t observe DST, and there are calls in a few other states to end the to end it the practice within their borders.

Adapting to new time zones usually takes the body about one day per hour of time difference, but some studies show effects lasting up to 10 weeks. Other research goes even further, indicating that the circadian system does not adjust to DST at all. So, as the body follows one clock, the calendar follows another, and the results may range between people from constant daytime sleepiness to lower quality sleep and even fatal car crashes.

Some tips to adjust your body and mind to waking up an hour before the usual time include going to bed earlier two night before the time change occurs, making sure you get at least seven to eight hours of sleep, avoiding alcohol and caffeine which can cause sleep disturbances, and avoiding long naps so you don’t disrupt your body’s natural sleep cycle even more.


To compile a list of health effects daylight savings time may have on a person’s health, 24/7 Wall St. reviewed over a dozen studies on the matter.

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