Putting the clocks forward in spring costs lives on US roads
The major ever study in to the ramifications of the transition to Daylight Saving Time (DST) in america estimates that abolishing it would prevent about 28 fatal car accidents a year.
The new findings appear in the journal Current Biology.
One of the arguments for putting the clocks forward by one hour in spring and again in fall is that it saves lives on roads. The explanation is that ensuring lighter conditions during the evening rush hour makes driving safer.
Scientists have linked the spring transition to DST to a number of problems, however, including increased threat of coronary attack, workplace accidents, and suicides.
This past year in the journal JAMA Neurology, for example, doctors reviewed the evidence how DST transitions affect the mind, heart, sleep patterns, and genes that control the sleep-wake cycle.
The authors then recommended abolishing DST transitions.
Fatal car accidents
Some studies have suggested that the spring transition increases automobile accidents, however the evidence has been inconsistent.
To resolve the problem, sleep scientists at the University of Colorado Boulder turned to the federal Fatality Analysis Reporting System, which recorded 732,835 fatal automobile accidents between 1996 and 2017 in U.S. states that observe DST.
They found an average 6% increase in the risk of fatal accidents in the week following transition to DST in spring each year. This percentage compatible 28 additional deaths per year.
Despite brighter driving conditions, there is no decrease in fatal accidents during the afternoon and evening following the clocks went forward.
The transition back again to standard amount of time in fall - when the clocks go back one hour - had no influence on the risk of fatal accidents.
“The public health impact of the DST transition regarding fatal traffic accident risk is clear from our data […]. Because our data only included the most extreme accidents, namely where a fatality was recorded, this estimation is likely an underestimation of the real risk.”
- Senior author Céline Vetter, University of Colorado Boulder
Mini jetlag
The increased risk was more pronounced in the mornings and in spots further west in a period zone.
In their paper, the scientists conclude from this that reduced natural light during the morning rush hour probably had little influence on the risk of fatal car accidents.
Rather, they attribute the increased number of fatalities to drivers not getting enough sleep. In addition they blame the disruption of drivers’ circadian daily rhythm, or body clock - a phenomenon they call “mini jetlag.”
Anytime of the entire year, accidents are more likely to occur between 6 a.m. and 8 a.m., which can be because of driver sleepiness. Putting the clocks forward in spring probably aggravates this effect, the researchers write.
In confirmed time zone, sunlight rises later in western regions, which might exacerbate the disruption of people’s circadian rhythm even more.
Benefits of abolishing DST
In the U.S., DST begins on the next Sunday of March and lasts for 8 months, before first Sunday of November.
The scientists conclude within their paper:
“Our results support the theory that abolishing time changes completely would improve public health insurance and reduce geographical health disparities, as seen in our time zone analysis.”
They acknowledge that the traffic accident data that they used for his or her analysis revealed nothing about the sources of individual accidents.
But they now hope to investigate the physiological ramifications of the clocks on individuals in greater detail, with a view to identifying the groups of folks most at risk from the transition to DST in the spring.
Source: www.medicalnewstoday.com
