Why do we move the clocks forward and back? Does daylight saving time actually save energy? And is it bad for our health? Find the answers below.
Daylight saving time was proposed by Benjamin Franklin in a humorous essay from 1784. However, it wasn’t seriously considered until around 1910.
Daylight saving time was first introduced in Austria and Germany on April 30, 1916, to save energy and thereby conserve oil, which was scarce due to World War I. Several European countries, including Denmark, followed suit on May 21 of the same year.
Daylight saving time returned during World War II, but it wasn’t until 1980 that it became a permanent fixture in Denmark. In 1996, daylight saving time was standardized across all EU countries. Today, around 70 countries worldwide have adopted the practice.
Winter time, or “standard time,” according to EU Commission regulations, always begins on the last Sunday in October and lasts until the last Sunday in March, when we switch to daylight saving time.
Does daylight saving time really save energy?
In recent years, several studies have suggested that daylight saving time does not actually save energy and may even result in a net loss.
Environmental economist Hendrik Wolff from the University of Washington in the USA co-authored a scientific analysis of Australia’s energy consumption during a period when parts of the country extended daylight saving time due to the Sydney Olympics in 2000, while others did not.
The researchers found that the measure reduced evening electricity consumption for lighting, but increased energy use in the dark morning hours—offsetting the evening savings.
Other studies indicate that daylight saving time has a positive effect. A 2008 report on daylight saving time, commissioned by the U.
S. Congress following an energy law from 2005 that extended the country’s daylight saving time, claimed that moving the clocks forward does save energy.
The extension of daylight saving time saved 1.3 terawatt-hours of electricity. This figure suggests that daylight saving time reduces the U.S.’s annual electricity consumption by 0.
03% and total energy consumption by 0.
02%.
These percentages may seem small, but they still represent significant savings due to the country’s enormous overall energy consumption.
Is daylight saving time healthy?
Supporters of daylight saving time have long argued that, regardless of energy savings, it promotes a more active lifestyle and thereby benefits public health—a claim that Hendrik Wolff and his colleagues are currently investigating further.
“In a nationwide American study on how people use their time, we clearly see that after the transition to daylight saving time in the spring, people watch significantly less television, while outdoor activities such as jogging, walking, and spending time in parks increase markedly,” says Hendrik Wolff.
“This is remarkable, as the total amount of daylight in a given day remains the same.
“
However, a 2008 study published in the New England Journal of Medicine concluded that the risk of heart attacks—in Sweden, at least—increases in the days immediately following the transition to daylight saving time in the spring.
“The most likely explanation for our findings is the disruption of sleep and interference with the biological rhythm,” says lead author Imre Janszky from the Institute of Public Health at the Karolinska Institute in Stockholm in an email to National Geographic News.
