With Daylight Saving Time (DST) ending recently, it’s timely we look at the available evidence to determine whether it’s good or bad for our health.
When was DST introduced?
DST was originally introduced during World War I as a wartime measure to conserve fuel and energy by extending daylight hours into the evening, reducing the need for artificial lighting.
DST operated nationally during World War I from 1 January 1917 to 25 March 1917 and during World War II for three summers, beginning on 1 January 1942. It was introduced again in NSW on 31 October 1971 after the Standard Time Act 1971 was passed by the NSW Parliament. Now on the first Sunday in October, people living in New South Wales, Victoria, South Australia, Tasmania and the Australian Capital Territory set their clocks forward by one hour to extend daylight hours after the working day. On the first Sunday in April, we set them back.
If you look at a world map, tropical regions have generally never had daylight saving and many other parts have stopped using it. Australia, New Zealand (which has probably had the longest continuous experience of DST), Europe and North America still put their clocks forward in spring and back in autumn.
The great debate
There are fierce debates about daylight saving in Australia. Western Australia, Queensland and the Northern Territory don’t have it. They claim that longer days in hot summers is oppressive, and farmers generally dislike the change in routine. Eastern and more southern states like the lifestyle benefits of being able to get outdoors or go to the beach after they come home from work.
Opponents of daylight-saving claim it’s bad for your health. So, what’s the evidence?
It swings about and is complicated by the effects of more hours of sunlight in summer and fewer in winter.
There’s some evidence of a small increase in heart attacks in the week after the clocks go forward in spring. Out of hospital cardiac arrests also go up after the spring shift but they go down after the autumn clock change, tending to balance it out. There is some evidence of injuries due to human error, but it may be more that the real shift is in time of day when injuries occur.
On the positive side, physical activity levels go up in areas with daylight saving.
So, the bottom line is that depending on your personal opinions for or against daylight saving, you can find evidence to support your position
