Should we scrap daylight saving time?

Most of us look forward to the extra hour we get in bed every October, but researchers argue that changing the clocks twice a year harms our health

- IAN TAYLOR

Human beings don't like change. As a species, we're a conservative bunch, very adaptable, of course, but ultimately fond of safe, predictable stasis. So it's odd that twice a year, every year, we inflict a big, fundamental change upon ourselves when we turn our clocks back in autumn and forward in spring. On paper, this biannual gear shift doesn't seem that significant - it's only an hour after all. But our bodies really don't like change. The negative effects on our wellbeing are such that many health researchers believe the sun needs to set on daylight saving time (DST) altogether.

Their reasoning? The clocks inside our bodies aren't as easy to change as the ones on our walls. Mounting research shows that artificially altering the time twice a year has a significant impact on our circadian health, interrupting the rhythm of the internal body clocks that keep many of our bodily functions ticking. When the clocks spring forward in March, for example, there's usually a 25-per-cent uptick in the number of heart attacks reported. It's thought disruption to our circadian clocks raises our blood pressure and the amount of cortisol, a stress hormone, in our systems, increasing the overall risk of a heart attack.

Other research suggests that circadian disruption interferes with our immune response, with the number of natural killer cells a person has falling when their body clock is knocked out of sync. When we gain an hour in October, the sudden onset of darkness also takes a toll. "Particularly among people of European ancestry, there are those individuals who suffer from seasonal affective disorder," says Dr John O'Neill, who studies circadian rhythms at the Medical Research Council Laboratory of Molecular Biology. "That's thought to be due to the times you see light. When you perceive that the day length is shorter, it signals you to be less active and this tends to lead to a lower mood."