Changing the clocks is linked to a plethora of health impacts – from heart attacks to car crashes.

As the nights draw in and we get ready to turn the clocks back, we can at least console ourselves with the thought of that extra hour in bed; the chance to snuggle under the duvet for just that bit longer. Getting one whole extra hour in the evening sounds great, after all – think of the things that can be achieved!

However, research shows it perhaps isn't what it's cracked up to be. After all, some studies show a link between the clocks going back in the autumn, and an increased risk of depressive episodes. On the positive side, at least turning the clocks back doesn't appear to be as bad for your health as turning the clocks forward, which is linked to increased heart attacks, strokes and road traffic accidents.

But let's back up a little. Daylight saving time (DST) was first introduced in the UK in 1916 during World War One, as a way to conserve energy and maximise the amount of daylight in the working day. As a result, the clocks go forward by one hour on the last Sunday in March, and backwards one hour on the last Sunday in October.

It isn't just a British phenomenon; around 70 countries and over a quarter of the world's population observe DST. In the US, DST was formally introduced in 1966. Today the clocks go forward on the second Sunday in March and the first Sunday in November.

Increasingly research suggests that clock changes may adversely affect people's health. The strongest evidence relates to pushing the clocks forward in spring, which makes the mornings darker and the evenings lighter, and robs people of an hour of sleep.

In 2014, researchers in the US found that the number of people admitted to hospital with a heart attack the Monday after the clocks were put forward. This finding has also been found in studies in Sweden, Croatia, Germany, Brazil, Finland and Mexico. A meta-analysis which pooled the results from all available studies calculated that the average number of heart attacks following the onset of DST in the spring appears to rise by a modest but significant 4%.

That isn't all. Other studies have shown that the number of strokes increases in the weeks immediately following putting the clock forward. While you might imagine that getting more light in the evening would be beneficial to mental health, that too has been challenged, with a 2020 study finding that the shift to daylight saving time exacerbates mood disorders, depression, anxiety and substance abuse.

Then we come to the issue of road traffic collisions. In the US, fatal car accidents have been shown to increase in the weeks following the spring clock change. One........

© BBC