A one-hour adjustment to the clock on the wall may not sound dramatic. But our biological clock begs to differ.
On Sunday, March 9, at 2 a.m. local time, the U.S. “springs forward,” moving the clocks ahead one hour as we enter daylight saving time. Most of us need a few days to adjust to time changes. In the meantime, we may suffer some consequences.
“Heart attacks and traffic fatalities increase in the days following the change to daylight saving time in the spring,” said biologist Erik Herzog, the Viktor Hamburger Distinguished Professor in Arts & Sciences at Washington University in St. Louis and past president of the Society for Research on Biological Rhythms, a scientific organization dedicated to the study of biological clocks and sleep.
Here, Herzog answers a few questions about the disruptions of daylight saving time and his view on a better path forward.
How does springing forward affect health?
People often complain about “losing” an hour of sleep and blame that for the consequences, but Herzog said it’s more complicated than that.
“There is evidence that people get less sleep following the shift to daylight saving time,” he agreed, but the problem is deeper. “Internally, you become desynchronized from the local time. You’re trying to get yourself on a new schedule with nothing in the world helping you.
“All we are doing is changing this thing on the wall and then asking your body to adjust to a new daily schedule with no clues from the environment,” Herzog said. “Similarly, you may notice that your pets continue to show up for their meals according to standard time because they schedule their days according to the sun and don’t read the clock on the wall.”
What’s happening in the body?
“Your biological clock, which controls your daily rhythms in things like sleep and wake, eating and fasting, interprets light in the morning as sunrise, and advances your wake-up time. Evening light tells your biological clock to wake up later the next morning,” Herzog explained.
In fact, people who live on the eastern edges of time zones and experience more morning sunlight tend to do better than those to the west — in terms of health, economics and other indicators of well-being, he said.
Current scientific data points to year-round standard time being the better option for health, but also for things like safety and learning in schools.
What is the current status of legislation?
“There has been growing enthusiasm for permanent standard time over permanent daylight saving time,” Herzog said. Along with a long list of societies of physicians and scientists, Herzog advocates for keeping standard time. “Currently, 21 states have permanent standard time bills in review. For the first time, most bills are for permanent standard time, instead of permanent daily saving time — although, like in Missouri, there are states with bills for both.
“Missouri has three bills for permanent standard time and two for permanent daylight saving time up for consideration,” he said.
What is holding us back from eliminating time changes?
“Any state can operate on permanent standard time. It requires an act of Congress to allow permanent daylight saving time,” Herzog said.
Some would like to see that change. At the federal level, U.S. Sens. Patty Murray, D-Wash., and Rick Scott, R-Fla., recently reintroduced the Sunshine Protection Act to end the twice-yearly time change and make daylight saving time the national year-round standard. The bill has been previously proposed during several sessions of Congress.
Herzog would prefer national adoption of permanent standard time.
“Although most folks want to end the confusing spring forward, it does require planning so that things like airplane schedules that are planned months in advance are not disrupted,” he said.
So, what can be done (besides moving to Arizona or Hawaii, where the clocks remain on standard time all year)?
“Avoid artificial light at the end of your day on the Saturday before the time change and seek bright light early on Sunday and on Monday,” Herzog said. “That will cause you to wake up earlier, helping your body more easily synchronize to the change.”
