- Each spring, people in the U.S. shift their clocks forward by 1 hour for daylight saving time.
- Scientists say this long-standing practice may actually be detrimental to our health and safety.
- Daylight saving time can disrupt our circadian rhythms, making us less alert and prone to illness or accident.
- Many sleep experts are calling for it to be abolished.
- In the meantime, a gradual shift in sleep schedule leading up to the time change may help minimize the effects.
On March 13, most of the United States — except for Arizona and Hawaii — “sprang forward,” adjusting their clocks ahead by 1 hour. Later this year, on Nov. 6, they will reverse the process by “falling back” 1 hour.
Daylight saving time (DST) is a practice that was first adopted by Germany on May 1, 1916, as a way to conserve fuel during World War I. It soon spread to the rest of Europe and eventually reached the United States 2 years later on March 19, 1918.
While daylight saving time has been going on for decades now, scientists have begun to realize that any benefits that it provides may be outweighed by its negative effects on human health and safety.
Dr. Susheel Patil, a clinical associate professor at the Case Western Reserve University School of Medicine who specializes in sleep medicine, said the time changes associated with daylight saving time typically cause us to lose sleep for about 1 week until we adapt to the change.
While we are going through this adjustment period, however, it can put our health and safety at risk.
“The loss of sleep has been shown to result in an increase in car accidents during the week after the change to DST, and there can be an approximately 20 percent increase in patient safety-related incidents associated with human error,” said Patil.
“In addition, DST has been linked to an increase in heart-related issues such as the acute occurrence of heart attacks, stroke, and atrial fibrillation,” he said.
Dr. Kristin Eckel-Mahan, an associate professor and circadian rhythm researcher with McGovern Medical School at UTHealth Houston, added that some studies have also shown an increase in workplace accidents in the week following the springtime change.
In addition, according to Dr. Andrea Matsumura, a sleep medicine physician at The Oregon Clinic and member of the American Academy of Sleep Medicine (AASM) Public Safety Committee, the seasonal time changes associated with DST can lead to mood disturbances as well as “cyberloafing” and reduced productivity.
Experts Healthline spoke with say it all comes down to circadian rhythm and the way daylight saving time disturbs that rhythm.
“Circadian rhythms are natural, internal cycles within the body that regulate physical, mental, and behavioral changes over a 24-hour cycle,” said Patil.
Circadian rhythms play a critical role in regulating sleep and wakefulness, and are influenced by our exposure to light and darkness.
They help ensure that we sleep at night and are awake during the day.
“Without a circadian rhythm, we would not be able to maintain long periods of wakefulness and sleep like most humans do,” said Patil.
Daylight saving time causes issues, according to Patil, because people usually wake up at a set time. When they must begin to wake up at what effectively is an earlier time, especially when it’s now darker than it used to be, this means the delicate balance of circadian rhythm is disrupted, leading to daytime sleepiness, said Patil.
“The effects are similar to a traveler flying between Chicago and Washington, D.C., and adjusting to the local time change,” he said.
On March 9, the Consumer Protection and Commerce Subcommittee of the House Energy and Commerce Committee held a hearing on daylight saving time with a panel of experts speaking about its effects on health and safety and whether it should be abolished.
Experts said they support the move to do away with daylight saving time.
Matsumura said her organization is in favor of abolishing daylight saving time completely. In the organization’s opinion, the best move would be to adopt permanent standard time.
In a 2020 position statement — which was endorsed by more than 20 medical, scientific, and civic organizations — the group stated that standard time is more aligned with our natural circadian rhythm and most conducive to public health and safety.
Patil agrees with the group.
“My personal opinion is that DST is antiquated and definitely not sleep- or circadian-friendly. This increases health and safety risks for our society with questionable economic benefits. It would be best to establish a permanent standard time,” Patil said.
Eckel-Mahan said she agrees that daylight standard time is not worth the health risks, pointing to studies showing that some people who have a late “owl” chronotype (staying up late and getting up late) never really adjust completely to daylight saving time.
“This may put some individuals at higher risk of metabolic disease,” she said.
Until laws throughout the United States change, however, many people will continue to be affected by sleep deprivation during the spring shift to daylight saving time.
Experts said there are several things you can do in the meantime to help reduce your fatigue following the time change.
Eckel-Mahan suggests beginning to adjust your schedule a few days ahead of time by going to bed slightly earlier and waking up slightly earlier each day.
“This will slowly shift your melatonin secretion and will make it easier to adjust to the abrupt hour of sleep loss you might otherwise experience,” she said.
Food intake is also a prominent driver of our peripheral circadian clocks, such as in the liver, kidney, and fat tissue, said Eckel-Mahan. You can begin to shift your mealtimes as well.
Patil further suggests making sure you are getting enough sleep each night of this process — about 7 to 8 hours.
In addition, he recommends getting bright light exposure when you wake up on the Sunday of the time change and for the next several days after.
“The exposure to bright light will reset your circadian system,” Patil said.
In addition to the above, Matsumura suggests dimming your lights and minimizing your use of screens during the hour leading up to bedtime.
Bright light can send a message to your brain to be awake, which is the opposite of what you need if you are winding down to sleep.