We all like the light evenings and dread the clocks going back, but it has now been shown that more hours of waking daylight may be beneficial to our health. Research published today (just before the end of UK daylight saving) shows that permanent adoption of daylight saving could increase the amount of physical activity in children.
Activity was recorded in over 23,000 children aged 5–16 years from nine countries (including Australia, England, Norway, Portugal and USA) using electronic devices that measure body movement. The levels of activity were then compared according to the time of sunset and were shown to drop markedly when sunset was brought forward by an hour.
It was found that the children’s total daily activity levels were 15-20% higher on days when the sun set after 21:00 than on days with sunsets before 17:00. The difference was still evident after adjusting for weather conditions and was particularly marked in European and Australian populations. The researchers estimated that extending evening daylight by one hour would provide 200 extra waking daylight hours per year and increase the level of moderate-to-vigorous physical activity by 6% per child per day.
The study author Anna Goodman, of London School of Hygiene & Tropical Medicine, said:
This study provides the strongest evidence to date that, in Europe and Australia, evening daylight plays a role in increasing physical activity in the late afternoon and early evening – the ‘critical hours’ for children’s outdoor play. Introducing additional daylight savings measures would affect each and every child in the country, every day of the year, giving it a far greater reach than most other potential policy initiatives to improve public health.
The effect of sunset time on children's activity levels applied equally to girls and boys, irrespective of weight, and across different socio-economic backgrounds.
Ashley Cooper, Professor of Physical Activity and Public Health at the University of Bristol, concludes:
While the introduction of further daylight savings measures certainly wouldn't solve the problem of low physical activity, we believe they are a step in the right direction.
Proposals to permanently shift the clocks forward by an hour have been debated in both the UK and Australia. By demonstrating that the introduction of additional daylight saving measures in Europe and Australia could yield worthwhile public health benefits, this study may provide additional support in favour of such a move.
Goodman A, et al. Daylight saving time as a potential public health intervention: an observational study of evening daylight and objectively-measured physical activity among 23,000 children from 9 countries. International Journal of Behavioral Nutrition and Physical Activity 2014, 11:84. Available at: http://www.ijbnpa.org/content/11/1/84