Daylight Saving Time: As Clocks Spring Forward, So Do Physical and Mental Health Risks

Mar 4, 2020

Daylight savings time springs clocks forward this weekend, and research shows that the lost hour of sleep can be more than inconvenient - it can be severely detrimental to physical and cognitive health. Murray State professor of psychology. Dr. Michael Bordieri, visits Sounds Good to discuss.

Daylight saving time was first implemented in the United States in 1918. Also called "war time," it's purpose was to conserve fuel and was discontinued nationally after the end of World War I. World War II began shortly after, during which Roosevelt instituted a national, year-round daylight saving time on February 9, 1942. States pushed for the right to abide by their own state-set clocks by repealing the legislation in 1945. It wasn't until 1966 that Lyndon B. Johnson passed a law setting a standard time that superseded state-held habits.

The U.S. was not the first country to implement daylight saving time.  Canada first used the system in 1908, but Germany and Austria popularized the practice in 1916. Soon after, other European countries followed suit. Even the Roman empire implemented a similar system centuries prior. 

Fifty-four years after Johnson's nation-wide mandate, daylight saving time is now a normal, albeit inconvenient, aspect of seasonal shifts. However, research suggests that losing an hour of sleep each spring can prove risky and, at times, even fatal. 

"[Daylight saving time] is associated with a whole host of bad outcomes," Bordieri explains. "At least in the spring. It doesn't mean that the day itself or the name 'daylight saving time' is a problem. It's actually a really interesting way psychologists and researchers have been able to look into the importance of sleep."

"What daylight saving time shows us is how important sleep is to our psychological and physical health," Bordieri continues. "When you try to study something at the level of the population, sleep quality varies. Some people get a great night's rest, others don't, but daylight saving time...clusters most people across the United States together and takes away one hour of their sleep all at once. When researchers go in and look at big data sets, they can find patterns about what that loss of sleep does to our psychological and physical health."

While ethical research practices prevent researchers from finding complete demonstrative evidence by forcing sleep/depriving sleep in subjects, a strong correlation can be found between increased health problems and a lack of sleep. This includes an increased risk of heart attacks, which are "more common the day after daylight saving time than almost any other day of the year," Bordieri says. 

"It's our psychological health as well," Bordieri explains. "We know that our ability to concentrate, to problem solve, is really closely linked to sleep as well. In fact, when you look at things like accidental deaths, there's a whole increase in accidental death rates that same day after you spring ahead. Things like motor vehicle accidents. There's an association where there's more car accidents occuring right after daylight saving time. Why? Again, it seems to hint at the role that sleep plays in our ability to make decisions [and] navigate our world."

Similar correlations have been found in smaller groups, including individuals traveling to different time zones (the term jet lag was believed to be coined as far back as the 60s). Traveling athletes have been found to be at a disadvantage at their own sport due to their shifting sleep cycles. Another study found new parents to be six times more at risk of getting into a motor vehicle accident within the first one hundred days of the baby's life. First responders, medical personnel, and factory workers are also at risk for increased physical and mental health problems when abruptly switching from night shift to day shift

With daylight saving time, one hour is lost, but the adverse effects of sleep deprivation can set in with even small increments of sleep loss over a larger amount of time. Even inconsistent or temporarily-deprived sleep cycles can result in "memory difficulty, difficulty focusing, and an increased risk for various health conditions," Bordieri says. To combat this, Bordieri suggests building routines that work to protect, not lose, sleep. 

"For example, getting screens away at least an hour (preferably two hours) before bed. Making sure that we're avoiding alcohol and caffeine, or even vigorous exercise, right before the bedtime hour. Kids don't like bedtimes, but as adults, it might be the best thing for us. To really make sure we're protecting our sleep, because a whole host of benefits can happen when we're well-rested. We're better able to solve problems. We're healthier. There's some research that suggests we're happier as well. We really don't want to discount sleep," Bordieri concludes.