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- To match their waking hours on the clock to the availability of daylight, people in many temperate countries set their clocks one hour ahead in summer and reset it in winter.
- This concept of ‘daylight saving’ has roots in energy efficiency and manipulating productivity.
- However, the shift back and forth is often a hassle, and there can be negative health effects too.
- The US Senate recently passed a law – the Sunshine Protection Act – to make daylight saving time permanent in the country from November 2023.
Kochi: Every summer, as daylight starts earlier, people in the northern hemisphere and some in the south set their clocks ahead by an hour. In autumn, just before winter sets in with its longer nights, they fall back one hour, to match standard time.
This effort to match waking hours to daylight is called daylight saving, and the result is daylight saving time (DST). But simple as this sounds, there are controversies surrounding this switch between DST and standard time. Some claim its benefits include saving energy consumption, but others are opposed to it for the hassle, including some negative health consequences.
Currently, around 70 countries implement DST to capture these benefits.
More recently, on March 15, DST was in the limelight after the US Senate passed a law to make DST permanent. This would mean Americans will not need to reverse their clocks back and forth every year anymore.
What’s the big deal about changing time? How does daylight saving help, and why is there a need to permanently shift to DST?
Saving energy
By one account, ‘daylight saving’ as a concept first emerged in the 1700s, when scientist and inventor Benjamin Franklin suggested that the French change their sleep schedules to save money on candles and lamp oil.
But the first person to employ daylight saving was possibly Wilhelm II, the last German ruler and king of Prussia. In 1916, when World War I was on, war factories had to work overtime to increase production. More hours in the day meant that workers could be put to work for more time.
Less devious though are the energy benefits that switching to DST are known to bring. Studies, like one published in 2017, show that adopting DST can reduce electricity consumption. This is because there are still a few hours of sunlight left when people get home from work when DST has been adopted. This means they consume less power in the evenings.
A 2020 study also said there are health benefits to adopting DST. More sunlight in the day could mean more time to squeeze in exercise, or time in the outdoors, which benefit both physical and mental health.
But others have placed more importance on DST’s side effects. The summer transition from standard time to DST and the transition back in the fall have numerous health effects.
One hour may not seem like much, but it’s enough to throw the human body’s circadian rhythms off. It means one hour less of sleep and rest, and it takes a couple of days for the body to adjust to the change. This alteration in schedules, including of sleep, has been linked to irregular heartbeats in people, even an increased risk of heart attacks.
In some areas, there have been reports of more fatal road accidents as a result.
Making DST permanent
Taken together, the US Senate passed its law – called the Sunshine Protection Act – to make DST permanent from November 2023. As a result, Americans will not need to shift between standard time and DST anymore. They will be permanently on DST from then.
This isn’t the first time the US has tried to switch completely to DST, according to NPR. In the early 1970s, the US had an energy crisis and decided to adopt DST permanently to reduce energy consumption. But the government quickly reversed its decision less than two years later. The plan wasn’t working: it didn’t reduce electricity usage.
One of its effects was that the country had to follow DST for the whole year, not some months. This meant the US had to go to school and offices when it was still dark. In fact, in the winter of 1973, more children were killed by cars in the early mornings as they walked to school in the dark, according to Scientific American.
Given these concerns, some scientists have said it might be better to make standard time permanent, instead of DST. This is also because standard time could be more suited to human circadian rhythms than DST.
However, others have said that it makes sense to retain the existing system: to follow standard time as usual and shift to DST between summer and fall.
For all questions, only time will tell – standard or daylight.