Happy New Year. Why not resolve this year not to be fooled by apparent risks, rather than real ones? Let's start with running a marathon. Everyone knows (because the media reports it) that every so often a healthy marathon runner drops dead during the race. And before we can think it through, we come to assume that marathon-running is a risky sport. Well, a new report suggests it's not as serious as taking the automobile.

Canadian researchers report in the British Medical Journal on their study comparing the risks of sudden cardiac death during a marathon run with the risk of dying in a motor accident that might have occurred if the roads hadn't been closed for the race.

The data came from marathons run on public roads with at least 1000 runners over the last 20 years. Of over 3.2 million runners, 26 had sudden cardiac death, equivalent to 0.8 deaths per 100,000 runners. Because of road closures, an estimated 46 accidental deaths were prevented, which is equivalent to a 35% reduction in relative risk of running rather than driving (or being driven). Put another way, 1.8 crash deaths were saved for every runner who dropped dead. So get training! After all, road accidents are something that happen often and repeatedly, and yet we manage to continue to ignore them. Walking or running to your destination (or even - gasp! - using public transport) may be a safer way to get there.