This year, daylight saving time begins at 2 am on March 8. Here, Elizabeth Klerman, MD, PhD, of the MGH Department of Neurology, discusses possible side effects of the clock “springing forward” – moving forward by one hour – and how people can ease the transition.

Can daylight saving time impact one’s health?

Yes, daylight saving time can adversely impact our health both acutely and chronically. During the first few days, people enjoy the sunlight when they leave work, but they also complain about additional fatigue in the morning. Most people are not aware on a daily basis of the other adverse consequences.

The acute change occurs when we “spring ahead” and therefore lose one hour of local clock time. Since we need to go to work an hour earlier – by body clock time – usually people chose to lose one hour of sleep. As a result, studies show people experience adverse cardiovascular events and the number of traffic accidents increase in the first week after the transition.

There also can be chronic effects. Even one hour of mismatch between local clock time and body clock time has negative health impacts, including increased metabolic diseases, cardiovascular disease, cancer and worsened mood regulation and performance.

What can people do to ease the side effects?

For the acute side effects – especially at the spring change –  people should try to sleep at least one hour later by clock time on the first few mornings after the clock change. To ease the chronic side effects of the mismatch between local clock, sun clock and biological clock, people should sleep more on their non-work days, preferably until they wake up naturally without an alarm clock.