Explained: What is Daylight Saving Time?https://indianexpress.com/article/explained/explained-what-is-daylight-saving-time/

Explained: What is Daylight Saving Time?

The rationale behind setting clocks ahead of standard time, usually by 1 hour during springtime, is to ensure that the clocks show a later sunrise and later sunset — in effect a longer evening daytime.

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The clock faces on the Pembroke Clock Tower are seen in Pembroke, Malta. Reuters/Darrin Zammit Lupi/File Photo

Why do many countries set their clocks 1 hour ahead?

At 2 am local time in most parts of the United States Sunday (Monday afternoon in India), Americans set their clocks an hour ahead. This is called daylight saving time, followed in over 70 countries on various dates, according to timeanddate.com. India does not follow daylight saving time; countries near the Equator do not experience high variations in daytime hours between seasons. In the US, where it is practised everywhere except in Hawaii and most of Arizona, it starts this year on March 10 and ends on November 3, when clocks will be set back to the original times.

The rationale behind setting clocks ahead of standard time, usually by 1 hour during springtime, is to ensure that the clocks show a later sunrise and later sunset — in effect a longer evening daytime. Individuals will wake an hour earlier than usual, complete their daily work routines an hour earlier, and have an extra hour of daylight at the end.

Timeanddate reports that it was followed by a group of Canadians on July 1, 1908, when residents of Port Arthur, Ontario, turned their clocks forward by an hour. Other locations in Canada soon followed suit. However, the idea did not catch on globally until Germany and Austria introduced DST on April 30, 1916, the rationale being to minimise the use of artificial lighting to save fuel during World War I.

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But does Daylight Saving Time actually save energy?

A century ago, when DST was introduced, more daylight did mean less use of artificial light. But modern society uses so much energy-consuming appliances all day long that the amount of energy saved is negligible.Various studies have been conducted on the benefits and disadvantages of DST. Among the biggest cons is disruption of the body clock or circadian rhythm. USA Today cited a study that found DST increases the risk of heart attack by 25%, while a return to original times lowers the risk by 21%. It quoted Timothy Morgenthaler, a sleep medicine researcher, as that disrupted sleep patterns might affect memory, learning, social interactions and overall cognitive performance.