The following essay is reproduced with permission from The conversationan online publication covering the latest research.
As people across the US prepare to advance their clocks one hour on Sunday, March 12, 2023, I find myself preparing for the annual ritual of media stories about interruptions in daily routines caused by the change of standard time to summer time.
About a third of Americans say they don’t expect these time changes twice a year. and almost two thirds I would like to remove them completelycompared to 21% who aren’t sure and 16% who would like to keep moving their clocks back and forth.
But the effects go beyond simple discomfort. Researchers are finding that “moving forward” each March is linked to serious negative health effects, including an increase in heart attacks other teen sleep deprivation. By contrast, the fall transition to standard time is not associated with these health effects, as my coauthors and I noted in a comment 2020.
I have studied the pros and cons of these rituals twice a year for over five years as a professor of neurology and pediatrics and the director of the sleep division at Vanderbilt University Medical Center. It has become clear to me and many of my colleagues that the transition to daylight saving time each spring affects health immediately after the time change and also during the almost eight months that Americans remain on daylight saving time.
The strong case for permanent standard time
Americans are divided on whether I prefer permanent daylight saving time either permanent default time.
However, the two time changes, as shocking as they are, are not the same. Standard time is closest to daylight, with the sun directly overhead at or near noon. Conversely, during daylight saving time from March to November, the clock shift resulting from daylight saving time causes daylight to be present one hour later in the morning and one hour later in the evening based on clock time. .
Morning light is essential to help establish the body’s natural rhythms: wakes us up and improves alertness. Morning light also improves mood: light boxes that simulate natural light are prescribed for morning use. to treat seasonal affective disorder.
Although the exact reasons why light activates us and benefits our mood are not yet known, this may be due to the effects of light on increased cortisol levelsa hormone that modulates the stress response or the effect of light in the tonsila part of the brain involved in emotions.
Teenagers can also be chronic sleep deprivation due to school, sports and social activities. for example, many Children start school around 8 am or before. This means that during daylight saving time, many young people get up and travel to school in total darkness.
The body of evidence makes a good case for adopting permanent standard time across the country, as I tested in a March 2022 Congressional Hearing and argued in a recent position statement for the Sleep Research Society. The American Medical Association recently called for permanent standard time. And at the end of 2022, Mexico adopted permanent standard time,, citing benefits for health, productivity and energy savings.
The biggest advantage of summer time is that it provides an extra hour of daylight in the late afternoon or evening, depending on the time of year, for sports, shopping, or outdoor dining. However, exposure to light late into the night for nearly eight months during daylight saving time comes at a price. This prolonged night light delays the brain’s release of melatonin, the hormone that promotes sleepiness, which in turn interferes with sleep and makes us sleep less in general.
Because puberty also causes melatonin to be released later in the nightwhich means that adolescents have a delay in the natural signal that helps them fall asleep, adolescents are particularly susceptible to sleep problems of the extended afternoon light. This change in melatonin during puberty lasts until the age of 20.
The West Rim Effect
Geography can also make a difference in how daylight saving time affects people. One study showed that people who live on the western edge of a time zone, who receive light later in the morning and later at night, I slept less than their counterparts in the far eastern part of a time zone.
This study found that Western Rim residents had higher rates of obesity, diabetes, heart disease, and breast cancer, as well as lower per capita income and higher health care costs. Other research has found that rates of certain other types of cancer are higher at the western edge of a time zone.
Scientists believe that these health problems may result from a Combination of chronic sleep deprivation and circadian misalignment.” Circadian misalignment refers to a mismatch in timing between our biological rhythms and the outside world. In other words, the schedule of daily work, school, or sleep routines are based on the clock, rather than sunrise and sunset.
A Brief History of Daylight Saving Time
Congress instituted daylight saving time throughout the year during World War I and World War II, and once again during the energy crisis from the early 1970s.
The idea was that having additional light later in the afternoon would save energy by reducing the need for electric lighting. This idea has been ever since turned out to be largely inaccuratesince heating needs can increase in the morning in winter, while air conditioning needs can also increase in the late afternoon in summer.
Another daylight saving argument has been that crime rates drop with more light at the end of the day. While this has been shown to be true, the change is very small and the health effects appear to outweigh the benefits to society of lower crime rates.
After World War II, the designation of daylight saving start and end dates fell to state governments. However, because this created many rail scheduling and safety problems, Congress passed the Uniform Time Act of 1966. This law set DST dates nationwide from the last Sunday in April to the last Sunday in October. in 2007, Congress changed the law to extend the period of validity of summer time from the second Sunday in March to the first Sunday in November, dates that remain in effect to this day.
However, the Uniform Time Act allows states and territories to opt out of daylight saving time. Arizona and Hawaii are on permanent standard time, along with Puerto Rico, the US Virgin Islands, the Northern Mariana Islands, Guam, and American Samoa.
Now many other states are considering whether to stop going back and jump forward. Several US states have legislation and resolutions under consideration to support permanent standard time, while many others have been or are taking into account permanent summer time. Legislation and rulings for permanent standard time have increased from 15% in 2021 to 31% in 2023.
In March 2022, the US Senate approved the Sun Protection Law in an attempt to make daylight saving time permanent. But the House did not move forward with this legislation. Florida Senator Marco Rubio introduced the bill on March 1, 2023.
The increase in activity among states seeking to break with these biannual changes reflects how more people are recognizing the inside of this practice. Now, it’s up to lawmakers to decide whether to end daylight saving time entirely and choose permanent standard time or daylight saving time.
This article was originally published on The conversation. Read the Original article.
