Daylight Saving Time: When to Change Your Clocks and How to Prepare for Health Effects

Get ready to “fall back.”

Daylight Saving Time 2024 ends at 2 a.m. this Sunday, November 3rd. Most people in the US change their clocks on Saturday evening, setting them back an hour to get 60 minutes more sleep (or another hour of fun). This means that there is more daylight in the morning, but it also gets darker much earlier at night.

Here you'll find everything you need to know, including how to prepare for the health effects of the time change.

When to turn back your clocks

Daylight saving time, also known colloquially as “summer time,” begins on the second Sunday in March and ends on the first Sunday in November. We always “jump forward” (lose an hour) when Daylight Saving Time begins and “fall back” (gain an extra hour) when it ends.

For manual clocks, it is recommended to set them back one hour before bedtime on Saturday evening (November 2nd) so that all clocks show the correct time when you wake up in the morning. Digital devices such as computers, cell phones and televisions will automatically set the time back a full hour at 2 a.m. on Sunday.

Health effects

The most notable change at the end of Daylight Saving Time is that there will be more daylight in the morning as children go to school and adults go to work. This also means that sunset immediately shifts an hour earlier. In Syracuse, sunrise goes from 7:38 a.m. on Halloween (Thursday, October 31) to 6:42 a.m. on Sunday, November 3, while sunset jumps from 5:56 p.m. on Thursday to 4:53 p.m. on Sunday.

For most people, it's easier to “fall back” for an hour than to “jump forward,” but your body's internal clock still needs to adjust. The Associated Press notes that studies have found that heart attacks and strokes tend to increase immediately after Daylight Saving Time begins in March, while sleep disorders and depression (including seasonal affective disorder) may be more common in the shorter days of fall and winter.

“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 are more alert. The patterns change with age, one reason early risers turn into hard-to-wake teenagers,” writes the AP.

“The morning light resets the rhythm. In the evening, levels of a hormone called melatonin begin to rise, causing sleepiness. Too much light in the evening – that extra hour compared to daylight saving time – delays this increase and the cycle gets thrown out of sync. And this circadian clock influences more than just sleep, it also influences things like heart rate, blood pressure, stress hormones and metabolism.”

Here's how to prepare

In addition to preparing by manually changing the clock, some recommend gradually shifting bedtimes in the days leading up to the time change. Ensuring you get the same amount of sunshine or more can also help reset your circadian rhythm for healthy, restful sleep.

Lack of sleep is linked to heart disease, cognitive decline, obesity and other health problems. The AP reports that one in three adults in the U.S. gets less than the recommended seven or more hours of sleep per night, and more than half of teenagers don't get the recommended eight or more hours of sleep during the week.

Also: Replace the batteries in your smoke detectors. The New York State Firemen's Association recommends changing batteries when we transition to or from daylight saving time because 60 percent of home fire deaths occur in homes without working smoke alarms.

Why do we still change our clocks?

Daylight saving time was first introduced during World War I to save fuel for the war industry. The law was repealed after the end of World War I, but was reinstated by Congress during World War II due to energy consumption, and became United States law in 1966 when President Lyndon B. Johnson signed the Uniform Time Act, establishing uniform start and end times within Zones set according to standard time. The policy, regulated by the Department of Transportation, aims to save energy and reduce car accidents and crime.

Some states do not change their clocks: Arizona (except the Navajo Nation), Hawaii, and the U.S. territories of Puerto Rico, Guam, American Samoa, the Northern Mariana Islands, and the U.S. Virgin Islands do not observe daylight saving time. They observe standard time year-round, while other states (including New York) observe standard time for half the year and daylight saving time for the other half.

The U.S. Senate passed a bipartisan bill called the Sunshine Protection Act in 2022, but it was never introduced in the House of Representatives after lawmakers could not agree on maintaining standard time or making daylight saving time permanent. Similar bills have been introduced in the New York Legislature to end the time change in the Empire State, but no progress has been made.

Some health experts say eliminating daylight saving time (or making it permanent) in other states would be a “bad idea.” A neurologist and spokesman for the American Academy of Sleep Medicine said not changing the clocks would make most people in America feel like they are suffering from “permanent jet lag.”