Daylight saving time is coming to an end again. Here’s how the time change can affect you

An extra hour of sleep is on the way for most Americans, although the “return” to standard time will also bring darker afternoons.

A tip: try to go outside to enjoy the sun in the morning: this will help your body clock reset more quickly.

LEARN MORE: America has already tried permanent daylight saving time. Could this work now?

Daylight saving time ends on Sunday at 2 a.m. local time, which means you need to set your clock back an hour before going to bed. Standard Time will last until March 14, when we will “forward” again with the return of Daylight Saving Time.

There are a lot of complaints about time changes twice a year. An AP-NORC poll last year found that just 12 percent of U.S. adults favored it, while nearly half opposed it. Lawmakers in Washington took up the issue again over the summer.

People often find the spring change more difficult, losing that hour of sleep we’re supposed to get back in the fall. But many people also mourn the end of daylight saving time in the fall, when days are already getting shorter and moving the clocks can mean less daylight after school or work for exercise or outdoor fun. The poll finds that, if forced to choose, most Americans would prefer to keep that extra hour of daylight in the evening.

But health groups, including the American Medical Association and the American Academy of Sleep Medicine, have long advocated adopting standard time year-round. That’s because it aligns more with the sun, which rises later in winter, and human biology, something called the circadian rhythm. Brighter mornings and less light at night are key to keeping that rhythm on track, making it easier to wake up on time and stick to healthy sleep habits.

Most countries do not observe daylight saving time. For those that do – primarily in North America and Europe – the date the clocks are changed varies. In the United States, Hawaii and most of Arizona do not change and remain on standard time.

Here’s what you need to know about the biannual ritual.

How the body reacts to light

The brain has a master clock that is set based on exposure to sunlight and darkness. This circadian rhythm is an approximately 24-hour cycle that determines when we become sleepy and when we are more alert. Patterns change with age, one reason why young people who mature early become difficult-to-wake teenagers.

Morning light is essential for synchronizing this internal clock. In the evening, levels of a hormone called melatonin begin to increase, triggering sleepiness. Too much light in the evening – whether outside later in daylight saving time or from artificial light like computer screens – delays this increase and the cycle becomes out of sync.

And this circadian clock affects more than just sleep, also influencing things like heart rate, blood pressure, stress hormones, and metabolism.

How do time changes affect sleep?

Even a change of time on the clock can disrupt sleep schedules, because even though the clocks change, the start times for work and school remain the same.

Just after the spring change, darker mornings and lighter evenings make it harder to fall asleep on time. Those early days were associated with an increase in car accidents and even a slight increase in heart attacks.

LEARN MORE: Trump urges calling Arkansas Sen. Tom Cotton to get permanent DST

In fall and winter, some people with seasonal affective disorder, a type of depression usually linked to shorter days and less sunlight, often struggle.

Many people adapt easily to the clock change, such as when recovering from jet lag after traveling. But a change in schedule can add pressure on shift workers whose schedules are already out of sync with the sun, or those who are regularly sleep deprived for other reasons.

About one in three American adults sleep less than the recommended seven hours a night, and more than half of American teens don’t get the recommended eight hours on weeknights.

Chronic sleep deprivation is linked to heart disease, cognitive decline, obesity and many other problems.

How to prepare for the time change

In the fall and spring, changing bedtime by as little as 15 minutes per night in the days leading up to the change can help make it easier to get used to.

But morning sunlight is essential for resetting your circadian rhythm and promoting healthy sleep. If you can’t go out, sit near the windows.

Will the United States ever get rid of the time change?

Every year there is talk of ending the time change. The nation even tried this solution in the 1970s, but it lasted less than a year after a public outcry.

The latest attempt came in July, when the U.S. House of Representatives overwhelmingly passed the Sunshine Protection Act, which would make daylight saving time permanent. President Donald Trump supports the idea and is pressuring reluctant senators to support it, even posting the cell phone number of Arkansas Sen. Tom Cotton, an opponent, on social media.

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