The case for permanent standard time

At 2 a.m. on Nov. 6, most of the United States will “fall back” to standard time.

More than 80 medical, education and religious organizations, including the American Academy of Sleep Medicine and Society for Research in Biological Rhythms, would like to see the nation embrace standard time year-round.

Hundreds of scientific studies show the seasonal clock change to daylight saving time triggers persistent misalignment of body clocks, leading to increased rates of heart attacks, cancer, diabetes, obesity, depression, substance abuse and suicide attempts. By contrast, the earlier sunrises and sunsets of standard time yield lower health care costs, lower traffic fatalities, and greater energy savings.

Three in four Americans want to end the twice-yearly time change. About 43 percent of a representative sample of 1,083 U.S. adults said they preferred year-around standard time, while 32 percent wanted permanent daylight saving time, according to a 2021 survey conducted by The Associated Press-NORC Center for Public Affairs Research.

Daylight saving time’s name evokes summertime pleasures, outdoor recreation and childhood memories of playing outside until dusk, but daylight saving time still is a con.

It doesn’t save time or daylight. Day length stays the same year-round. So does the amount of daylight on any given day. Daylight saving time simply shifts light from the morning to the evening. From the second Sunday in March until the first Sunday in November, we pretend the sun rises and sets an hour later than it does.

Our minds may tolerate that, but our brains know better. They remain on sun time, which is aligned more closely with standard time. At noon on standard time in the middle of each time zone, the sun is directly overhead. Morning sunlight, the body’s most potent time-setting cue, tethers us to the Earth’s 24-hour day/night cycle. Exposure to sunlight soon after we awaken governs inner clocks that control sleep, alertness, mood, body temperature, blood pressure, heart rate, hunger, cell division and hundreds of other bodily functions.

When we shift to daylight saving time, our morning light exposure drops. Our biological clocks fall out of sync.

We pay a price: Daylight saving time’s lighter, longer evenings make it harder to fall asleep. We sleep less. Darker mornings make it harder to awaken, shrug off drowsiness and feel alert.

A person living in New York City who typically gets up at 7 a.m. will be forced to awaken before sunrise 164 days a year on permanent daylight saving time, according to an interactive chart on the website of the nonprofit Save Standard Time.

While many people think of Florida as a sunshine state, even in Miami, on Florida’s southern tip, a person arising at 7 a.m. would awaken before sunrise a whopping 232 days a year on permanent daylight saving time. They’d miss exposure to the body clock-setting sunlight cue on awakening 7.6 months a year.

As a practical matter, a person who awakens around 7 a.m. without an alarm clock on standard time likely will need an alarm to awaken at the same clock time on daylight saving time. People who must awaken at their usual clock time for work or school get about 19 minutes less sleep during daylight saving time when they are more apt to both toss and turn and awaken more often.

One of us is a sleep specialist and neurologist and can see the consequences of sleep loss in patients. Some struggle to get to school on time, have difficulty focusing at work, find it hard to stay awake for family time, or strive to cope with depression or anxiety. Daylight saving time often makes their problems worse. Achieving better sleep can be life changing.

Teenagers and people who have to go to work or school before or at 8 a.m. or who work irregular hours bear the brunt of daylight saving time’s adverse impact on sleep. Teens notoriously experience chronic sleep deprivation, a consequence of pubertal changes in biological clocks that push them to stay awake until 11 p.m. or later, out of sync with their early middle and high school start times.

The Centers for Disease Control and Prevention’s (CDC) 2019 Youth Risk Behavior Survey found 78 percent of the nation’s high school students averaged less than the minimum of eight hours of sleep on school nights that sleep specialists recommend. On both standard time and daylight saving time, teens have to get up at the same clock time for school. On daylight saving time, it is even harder than it is on standard time for them to get enough sleep.

Many essential workers, including nurses and other health care providers, police, firefighters and other community service workers, as well as industrial workers and commercial drivers, are at particular risk for sleeping less when daylight saving time is in effect because they often follow non-standard work schedules. Minorities and people with lower incomes are twice as likely to be affected.

Sleepiness and misaligned body rhythms put people at higher risk of drowsy driving and making poor decisions that lead to speeding, texting while driving, and driving after drinking. If the U.S. were to adopt daylight saving time year-round, children would have to commute to school in the dark for about one-third of the academic year. Parents understandably shudder at seeing their children get behind the wheel of a car or wait for school buses in the dark.

In the spring and fall, extra evening light may reduce some traffic accidents during busy evening commutes, but poor sleep and out-of-sync body rhythms outweigh these benefits across the year. Areas where clock time lags behind sun time by at least 30 minutes have over 20 percent more fatal car accidents than those with closer alignment.

Commercial interests drive the push for permanent daylight saving time. Convenience stores and restaurants, along with industries promoting golf, tourism and other outdoor recreation activities, say business increases when daylight lasts later in the evening.

However, economics still favor permanent standard time. Increases in productivity, improved cognitive function and decision-making, reductions in workplace injuries as well as absences related to health issues, higher graduation rates, and educational attainment add estimated billions of dollars to the economy. Permanent standard time also reduces demand for heating and air conditioning, thereby saving American households money.

In the U.S., only Hawaii, most of Arizona, and the U.S. territories stay on standard time year-round. Around the world, about 70 countries observe summertime daylight saving time, although changes are on the horizon.

In October, a working group of European non-governmental organizations and researchers urged European Union member states to adopt permanent time zones as close as possible to their solar time. Also in October, Mexico’s Senate voted to abolish daylight saving time in favor of permanent standard time, making an exception for areas bordering U.S. states that observe daylight saving time.

Last March, in an unannounced voice vote, the U.S. Senate passed the Sunshine Protection Act, a bill authored by Sen. Marco Rubio (R-Fla.) calling for permanent daylight saving time. The House declined to advance the bill out of committee. If not acted on, it will expire when Congress ends its term in December.

Instead, sleep groups and other medical groups would like to see a bill calling for permanent standard time introduced in Congress next year. They’re calling their proposed legislation the “Sleep Protection Act.”

Indeed, we should stop switching the clock back and forth, but we must make the right move — a move to permanent standard time.

Karin Johnson, MD, is a professor of neurology at the University of Massachusetts Chan Medical School-Baystate and medical director of the Baystate Health Regional Sleep Program. She is a member of the Board of Directors of the nonprofit Save Standard Time and creator and host of its new educational video series, “The Science of Clock Change.”

Lynne Lamberg is a medical journalist and editor who writes frequently on sleep, biological clocks, and mental health. She is the book editor of the National Association of Science Writers.