How Springing Forward to Daylight Saving Time Could Affect Health

Most of America "springs forward" Sunday for daylight saving time, and losing that hour of sleep can do more than leave you tired and cranky the next day. It also could harm your health.

Darker mornings and more evening light together knock your body clock out of whack — which means daylight saving time can usher in sleep trouble for weeks or longer. Studies have even found an uptick in heart attacks and strokes right after the March time change.

When does daylight saving time start?

Daylight saving time begins Sunday at 2 a.m., an hour of sleep vanishing in most of the U.S. The ritual will reverse on Nov. 2 when clocks "fall back" as daylight saving time ends. Hawaii and most of Arizona don’t make the spring switch, sticking to standard time year-round along with Puerto Rico, American Samoa, Guam, and the U.S. Virgin Islands. Worldwide, dozens of countries also observe daylight saving time, starting and ending at different dates.

Some people try to prepare for daylight saving time’s sleep jolt by going to bed a little earlier two or three nights ahead. With a third of American adults already not getting the recommended seven hours of nightly shuteye, catching up can be difficult.

What happens to your brain when it’s lighter later?

The brain has a master clock that is set by exposure to sunlight and darkness. This circadian rhythm is a roughly 24-hour cycle that determines when we become sleepy and when we’re more alert. The patterns change with age, one reason that early-to-rise youngsters evolve into hard-to-wake teens.

Morning light resets the rhythm. By evening, levels of a hormone called melatonin begin to surge, triggering drowsiness. Too much light in the evening — that extra hour from daylight saving time — delays that surge and the cycle gets out of sync.

Sleep deprivation is linked to heart disease, cognitive decline, obesity, and numerous other problems. And that circadian clock affects more than sleep, also influencing things like heart rate, blood pressure, stress hormones, and metabolism.

How does the time change affect your health?

Fatal car crashes temporarily jump the first few days after the spring time change, according to a study of U.S. traffic fatalities. The risk was highest in the morning, and researchers attributed it to sleep deprivation.

Then there’s the cardiac connection. The American Heart Association points to studies that suggest an uptick in heart attacks on the Monday after daylight saving time begins, and in strokes for two days afterward.

Doctors already know that heart attacks, especially severe ones, are a bit more common on Mondays generally — and in the morning, when blood is more clot-prone.

How to prepare for daylight saving time

Gradually shift bedtimes about 15 or 20 minutes earlier for several nights before the time change, and rise earlier the next morning, too. Go outside for early morning sunshine that first week of daylight saving time, another way to help reset your body’s internal clock. Moving up daily routines, like dinner time or when you exercise, also may help cue your body to start adapting, sleep experts advise.

Afternoon naps and caffeine as well as evening light from phones and other electronic devices can make adjusting to an earlier bedtime even harder.

Will the U.S. ever eliminate the time change?

Every year there’s talk about ending the time change. In December, then-President-elect Donald Trump promised to eliminate daylight saving time. For the last several years, a bipartisan bill named the Sunshine Protection Act to make daylight saving time permanent has stalled in Congress; it has been reintroduced this year.

But that’s the opposite of what some health groups recommend. The American Medical Association and American Academy of Sleep Medicine agree it’s time to do away with time switches but say sticking with standard time year-round aligns better with the sun — and human biology — for more consistent sleep.

Conclusion

Daylight saving time can have a significant impact on our health, from sleep trouble to increased risk of heart attacks and strokes. By understanding how the time change affects our bodies and taking steps to prepare, we can minimize the negative effects and get back to our normal routines.

FAQs

• When does daylight saving time start?
  Daylight saving time begins Sunday at 2 a.m.
• How does the time change affect my health?
  The time change can lead to sleep deprivation, which is linked to heart disease, cognitive decline, and other problems. It can also increase the risk of fatal car crashes and heart attacks.
• How can I prepare for daylight saving time?
  Gradually shift your bedtime and wake-up time 15-20 minutes earlier, expose yourself to early morning sunlight, and adjust your daily routines to help your body adapt.
• Will the U.S. ever eliminate the time change?
  There have been efforts to eliminate the time change, but no bill has passed yet. Some health groups recommend sticking with standard time year-round, while others argue it’s better to keep the current system.