A 46–year–old Kandivli resident died after completing a halfmarathon in Thane on Sunday. On Monday, the runners’ fraternity was abuzz with reports that a second participant in the same marathon, too, had suffered a heart attack. The Mumbai Marathon last month had recorded a cardiac arrest as well. Should these race–related cardiac cases be a cause for concern or be written off as random incidents?

The US is concerned enough to undertake a study to examine the correlation between marathons and heart deaths. Called the Race Associated Cardiac Arrest Registry, its findings published in the New England Journal of Medicine (NEJM) last month include 59 deaths among 11 million runners who had participated in marathons or half–marathons between years 2000 and 2010. In other words, a death in every 2,59,000 runners in the US.

"Cardiac arrest, most commonly attributable to hypertrophic cardiomyopathy (thickening of the walls of the heart) or atherosclerotic coronary disease (development of blockages in arteries), occurs primarily among male marathon participants; the incidence rate in this group increased during the past decade," said the NEJM study. A recent Australian study found that 32% of the runners for the Perth Marathon had elevated levels of cardiac troponin, a substance whose presence in blood suggests cardiac injury.

Asenior doctor pointed out that such data makes it clear that marathons are associated with heart risks. City authorities should put a curb on the number of public marathons that can be held in the city every year, he added.

But the runners’ fraternity is not impressed with these argument. "Most runners who have an episode would have had a risk factor or symptoms that they may have chosen to ignore," said Dr Aashish Contractor, preventive cardiologist and medical director of the Mumbai Marathon.

Runners’ fraternity pointed out that cardiac arrests are not common. Even the New England Journal of Medicine study had suggested that despite the increase in the racerelated deaths in the past decade, the death rate is equivalent to or lower than the risk associated with other vigourous physical activities.

All runners need a proper health checkup. Dr Somnath Mallakmir, who is also an associate professor (cardiology) with D Y Patil Medical college in Vashi, said that people should undergo a complete medical checkup before taking up long–distance running. Dr Mallakmir, who is himself a marathon runner, said that people who have a risk factor —either smoking, family history, diabetes or obesity—should certainly get themselves evaluated.

"Ideally, people should start acclimatizing their body to the rigours of running a month or two before the actual run," he added.

Cardiologist Ganesh Kumar said that some Mumbaikars had the habit of literally getting out of their chair to run a race. "A thorough medical checkup is mandatory. There are enough diagnostic tests to rule out any heart problem."

Dr Contractor said, "For an actual event to occur, six risk factors need to come together and form a perfect storm as such in the body." So, the person should have plaque buildup in his arteries, he should have some problem with his blood clotting factors, he should have chronic diseases like diabetes or hypertension and he should have some stress–related problems. "Environmental circumstances like smoking or ingestion of drugs contribute to such storms that lead to cardiac arrest or heart attacks."