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Daylight saving time 2024: What to know about the time change and tips to protect your health

On March 10, 2024, we will enter daylight saving time and spring ahead. Losing an hour of sleep can harm your health. Here's what to know.
/ Source: TODAY

Daylight saving time 2024 is around the corner, and we’re about to “spring ahead.”

Losing that hour of sleep along with being on a new schedule can be jarring to your body. The clocks may be changing by just an hour, but it can still have a big impact on your day — and your health. 

That's because the change causes a phase shift of our circadian rhythm, the body’s internal clock, and exacerbates the chronic sleep deficiency Americans already experience, Dr. Carol Ash said on TODAY.

The effects are particularly evident in the spring, when people face a greater risk of heart attack and stroke in the days after losing one hour of sleep. There are also more car accidents, medical errors and hospital admissions.

To help make the adjustment a little easier, experts recommend going to bed a bit earlier in the days leading up to the change to prepare. They also suggest getting at least 15 minutes of morning sunshine when you wake up.

However you feel about the clocks changing, it helps to know a little more about why we do this every year — and why some sleep experts are calling for the practice to end.

When is daylight saving time in 2024?

Daylight saving time 2024 starts on March 10, 2024, when the clocks skip from 2:00 a.m. to 3 a.m. Daylight saving time 2024 lasts until Nov. 3, 2024, when clocks go from 2:00 a.m. back to 1 a.m.

Daylight saving time is an annual practice affecting most but not all Americans. It starts every year on the second Sunday in March and ends every year on the first Sunday in November, when we return to standard time.

How does daylight saving time work?

Daylight saving time works by moving clocks one hour ahead in order to have more sunlit hours in the evening during the warmest-weather months, according to the National Institute of Standards and Technology.

This allows us to maximize the amount of sunlight we get while we’re awake. The effect is more noticeable the farther you are from the equator, meaning northern states willfeel it more than southern states.

Contrary to popular belief, daylight saving was not introduced to help farmers get some extra sun. Instead, it was put in practice with the Standard Time Act of 1918 during World War I as a way to conserve energy, but the actual effects have been minimal at best, the Scientific American reported.

How long does daylight saving time last?

Daylight saving time lasts about eight months, from the second Sunday in March to the first Sunday in November.

Daylight saving time 2024 will last from March 10, 2024, to Nov. 3, 2024.

Which states don't observe daylight saving time?

According to the U.S. Department of Transportation, the following U.S. states and territories do not observe daylight saving time:

  • Hawaii
  • Most of Arizona
  • Puerto Rico
  • American Samoa
  • Guam
  • The Virgin Islands
  • Northern Mariana Islands

What happens if daylight saving time is permanent?

If daylight saving time was to be made permanent, there would be no changing of clocks twice a year. In addition to eliminating the practical hassle, this could have health benefits for many people.

Although it might seem like gaining or losing a single hour of sleep shouldn’t make much of a difference, it absolutely does. Studies have also shown an increase in heart attacks, car crashes and other ill health effects, particularly when clocks spring forward.

Some sleep health experts argue that permanent standard time would be preferable to permanent daylight saving time. Ash said we lose about 30 minutes of sleep a night during daylight saving time from March to November due to our bodies being misaligned with the sun.

The American Academy of Sleep Medicine is “in favor of a national, fixed, year-round time,” the organization’s website says. The best evidence we have now suggests that year-round standard time (rather than daylight saving time) “aligns best with human circadian biology and provides distinct benefits for public health and safety.”

We’ve made daylight saving time permanent before: In January 1974, President Richard Nixon signed the Emergency Daylight Saving Time Energy Conservation Act into law, which eliminated clock-changing for 16 months. While the move (designed as a two-year experiment) was initially quite popular, public opinion turned later in the year. Lawmakers ended the experiment early and standard time was reintroduced in October 1974.

More recently, the Sunshine Protection Act, which would make daylight saving time last all year, passed unanimously in the Senate in 2022 but failed to pass in the House of Representatives, so it wasn't signed into law. The bill was introduced again in 2023 but has since stalled.

Tips to reduce health effects of daylight saving time

You can reduce the negative health effects of daylight saving time by making some adjustments to your routine.

Before the time change:

  • Reconsider your bedtime: “Try going to bed 15 minutes earlier, starting two to three days before the time change. This will help make sure you are well-rested before the clock change so any resulting ‘sleep debt’ will feel less extreme,” Candice A. Alfano, Ph.D., director of the University of Houston’s Sleep and Anxiety Center of Houston, says.
  • Shift your wakeup call: “A few days before daylight saving time, set your wakeup time to 30 minutes ahead. This will narrow the difference and make it easier for you to adjust to the time change,” Dr. Ana Krieger, medical director of the Center for Sleep Medicine at Weill Cornell Medicine and New York-Presbyterian, says.
  • Shift your kids' schedules, too: Adjusting your kids' schedules in the days leading up to the change can help them adjust better and leave them feeling less drowsy for school on Monday morning, experts say.
  • Trick your brain: “The brain looks for visual cues to know what time it is. Another thing you can do is change the time on a wristwatch 15 minutes ahead each day before daylight saving time to provide that visual cue,” Ash said.

The day after the time change:

  • Avoid naps: “If you feel sleepy the day after the change, try to resist taking a nap because this will reduce the amount of sleep pressure present at bedtime and can create longer term sleep problems. If you must nap, keep it to 15 to 20 minutes, ideally in the late morning,” Alfano says.
  • Seek out sunshine: “Make sure you get plenty of sunlight on the morning after the change. Light has potent effects on our internal body clock and will help you feel less tired,” Alfano added.

The duration of daylight saving time:

  • Readjust your routine: “Take advantage of your earlier start for the day, and shift your activities to an earlier schedule, including dinner, exercise and bedtime,” Krieger suggests.
  • Watch your diet: “Avoid foods and beverages that will keep you up, such as caffeinated beverages, chocolates or alcohol at least three hours prior to bed,” Ash advises.
  • Avoid exercising too late: “Moderate-to-high intensity exercise should be performed earlier in the day, as late-night exercise can inhibit a good night’s sleep. During exercise, the sympathetic nervous system is activated, and when this occurs close to bedtime, it may also affect subsequent sleep propensity,” Mark Aloia, Ph.D., sleep psychologist at National Jewish Health, tells
  • Reduce screen time: “Light from a device can affect one’s circadian phase. If it’s nearing bedtime, our phase is shifting toward sleep and exposing ourselves to too much light at this time can result in trouble falling sleep. Screen time is also harmful for adequate sleep if the content we’re viewing is activating and anxiety provoking, which can interfere with emotions and interrupt sleep,” Aloia says.