Why daylight saving time can be unhealthy

On Sunday, the US switched over from standard time to daylight saving time (DST), with clocks already moved one hour ahead in many parts. 

However, not everyone is happy about it the switch which will continue until November when standard time returns.

Sleep scientists say even a small change can have an impact on Circadian rhythm – the body’s internal 24-hour body clock which regulates cycles of alertness and sleepiness by responding to light changes in our environment.

A disruption in Circadian rhythm can leave people feeling drowsy, moody, and with an increased appetite. This can leave our motor functions impaired – which can have real-world consequences.

A 2009 study showed a 3.6 per cent increase in mining workplace injuries on the Monday after the switch to daylight savings time.

Researchers have found that heart attacks and sleep deprivation in teens increase as the clocks “spring ahead” every March.

NPR quoted a study as showing that hospitalisations for atrial fibrillation increased in the aftermath of the change to daylight savings time.

The largest advantage daylight saving time offers is an extra hour of light until November. This is time people can use to stay out later playing sports, eating, or shopping.

However, the extra light postpones the release of melatonin (the sleep hormone) in the brain – which can be particularly damaging to teenagers who are already susceptible to sleep problems.

The twice-a-year ritual – no time change is observed in Hawaii, Arizona, Puerto Rico, the US Virgin Islands, American Samoa, Guam and the Northern Marianas – has led some members of Congress to push to make daylight saving time permanent.

The Senate in March passed a bipartisan bill, named the Sunshine Protection Act, to end the back and forth. The House has not acted on the measure. However, experts say making daylight saving time permanent is the wrong way to go.

The American Academy of Sleep Medicine and the American Medical Association in a recent statement said, “Standard time is closely aligned with the position of the sun, which is important for the body because sunlight is the most powerful external cue for the human circadian rhythm.”

Meanwhile, Americans remain divided on the subject. A poll conducted in October 2021 found that most people want to avoid switching between daylight saving and standard time, though there is no consensus behind which should be used all year.