Daylight saving time: When to change your clocks, how to prepare for health effects

Get ready to “fall back.”
Daylight Saving Time 2024 ends this Sunday, Nov. 3, at 2 a.m. Most people in the U.S. will change their clocks on Saturday night, turning them back an hour to get an extra 60 minutes of sleep (or another hour of fun). That means there’ll be more daylight in the morning, but it will also get darker much earlier at night.
Here’s everything you need to know, including how to prepare for the health effects of the time change.
When to turn your clocks back
Daylight Saving Time, also colloquially referred to as “daylight savings time,” begins on the second Sunday in March and ends the first Sunday of November. We always “spring forward” (losing an hour) when DST begins and “fall back” (gaining an extra hour) when it ends.
For manual clocks, it’s recommended to turn them back an hour before going to bed on Saturday night (Nov. 2) so that when you wake up in the morning all your clocks will tell the correct time. For digital devices, including computers, cell phones and TVs, the time will automatically change at 2 a.m. Sunday, going back a full hour.
Health effects
The most notable change of Daylight Saving Time ending is that there will more daylight in the morning as kids go to school and adults go to work. It also means sunset will immediately shift an hour earlier, too. In Syracuse, sunrise will go from 7:38 a.m. on Halloween (Thursday, Oct. 31) to 6:42 a.m. on Sunday, Nov. 3, while sunset will jump from 5:56 p.m. Thursday to 4:53 p.m. Sunday.
“Falling back” tends to be easier for most people than “springing forward” an hour, but your body’s internal clock will need to adjust all the same. The Associated Press notes that studies have found heart attacks and strokes tend to increase right after DST starts in March, while sleep struggles and depression (including seasonal affective disorder) can occur more often 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’re more alert. The patterns change with age, one reason that early-to-rise youngsters evolve into hard-to-wake teens,” the AP writes.
“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. And that circadian clock affects more than sleep, also influencing things like heart rate, blood pressure, stress hormones and metabolism.”
How to prepare
Besides preparing by manually changing clocks, some recommend shifting their bedtimes little by little in the days leading up to the time change. Making sure you get the same amount of sunshine or more can also help reset your circadian rhythm for healthy, restful sleep.
Sleep deprivation is linked to heart disease, cognitive decline, obesity and other health problems. The AP reports 1 in 3 U.S. adults get less than the recommended seven-plus hours of sleep a night, and more than half of teens don’t get the recommended eight-plus hours on weeknights.
Also: Replace the batteries in your smoke detectors. The Firemen’s Association of the State of New York recommends changing batteries when we switch to and from daylight savings time, as 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 established during World War I to conserve fuel for war industries. The law was repealed after WWI ended, but was re-established by Congress during World War II due to energy consumption and became U.S. law in 1966 when President Lyndon B. Johnson signed the Uniform Time Act, establishing uniform start and end times within standard time zones. The policy, regulated by the Department of Transportation, aims to save energy and reduce car crashes and crime.
Some states don’t change their clocks: Arizona (except for the Navajo Nation), Hawaii, and the U.S. territories of Puerto Rico, Guam, American Samoa, 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) spend half the year in Standard Time and the other half in DST.
The U.S. Senate approved a bipartisan bill known as the Sunshine Protection Act in 2022, but it never advanced in the House after lawmakers failed to agree on keeping standard time or making daylight savings time permanent. Similar bills have been introduced in the New York state legislature to end the changing of clocks 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 clocks would make most of America feel like it’s suffering “permanent jet lag.”