The tragic death of Claire Squires within sight of the finish line at last year’s London Marathon sparked a massive outpouring of generosity among visitors to herJustgiving.com page. It also sparked a frenzy of press interest and speculation.
Sudden deaths among athletes make headlines and grab attention precisely because they’re so rare: when the European Society of Cardiology (ESC) reviewed the research, they found the highest estimate of rates of sudden death in young athletes to be two in 100,000. This January, the New England Journal of Medicine published a study that puts the rate of death among 10 million US runners at just 0.54 per 100,000.
The medical director of the Virgin London Marathon (VLM), Professor Sanjay Sharma, says that the overall death rate for the VLM is one in 80,000. There have been just 11 deaths in 32 years of the race – and remember that as Britain’s biggest marathon, London attracts tens of thousands of novice runners of all ages and fitness levels. (It’s difficult to find research that allows for an exact like-for-like comparison, but in 2006, researchers at University College London reported estimated rates of sudden cardiac death among the general population to be one in 1000.)
Deaths among runners, then, are very rare, but they do occur – and heart problems are by far the most common cause. In athletes under 35, around 90 per cent of sudden deaths are due to underlying genetic heart conditions. Under the stress of training and the adrenaline of racing, these can trigger a cardiac arrest, a sudden crisis in which the heart can’t pump oxygenated blood out to the rest of the body. The remaining 10 per cent? This is accounted for by conditions including asthma, heat stroke and hyponatraemia (dangerously low levels of sodium).
In over 35s, sudden death is also largely a matter of the heart. But rather than underlying genetic problems, cardiac arrests in older athletes are much more likely to be caused by ischaemic (or degenerative) heart disease. It’s a problem usually caused when arteries are narrowed by plaque, thanks to a range of lifestyle risk factors including poor diet, high blood pressure, obesity and smoking. It also ups your risk of a heart attack, where the heart itself is starved of blood by a clot or other obstruction.
Your risk increases with age, and not just for runners: according to the Australian Institute of Health and Welfare, ischaemic heart disease kills more Australians than any other single disease (in New Zealand cardiovascular disease is the leading cause of death, according to The Heart Foundation). “The vast majority of the deaths at VLM have been men with signs of this type of degenerative coronary artery disease,” says Sharma.
So there’s a pretty stark divide: under 35, and sudden cardiac death is likely to be down to genes; over 35 and it’s almost exclusively degenerative disease influenced by age or lifestyle choices. While the risks of either event are very low, sudden cardiac death (SCD) among marathon runners is more common in men than women, in older athletes than the under 35s, and in people with risk factors for degenerative heart disease such as high blood pressure, high cholesterol or obesity.
This is why, on 22 April, 2012, as Sharma sprinted down Birdcage Walk being cheered on by spectators who mistook him for a racer, he was half expecting to see a 70-year-old man. “To find Claire Squires, an extremely young, athletic female, lying there lifeless was a real shock,” he says. “I was horrified.”
A 30-year-old female in good shape, Claire seemed the opposite of the type of marathoner most at risk of SCD. The truth is that her death wasn’t just an absolute tragedy. It was also a striking statistical anomaly.
Do You Run The Risk?
Use this quick guide from International Olympic Committee Medical Commission* to find out if you fall into one of the three at-risk groups
GROUP 1: Family History
Have any of your first-degree relatives (parent, sibling, offspring) under the age of 50:
Died suddenly and unexpectedly?
Been treated for recurrent fainting?
Had unexplained seizures, drowning or car accidents?
Had any form of heart surgery?
GROUP 2: Lifestyle Factors
Have you ever been told you have:
Diabetes?
High blood pressure?
High cholesterol?
Are you a heavy smoker?
GROUP 3: Symptoms
Have you ever felt dizzy, fainted or passed out when exercising?
Do you ever suffer chest tightness, coughs or wheezing during or after a run?
Have you ever been treated/hospitalised for asthma?
Have you ever had a seizure?
Have you ever had racing of the heart or skipped heartbeats?
Do you tire faster than you would otherwise expect?
Have you ever been told you have a heart murmur or arrhythmia?
Have you had a severe viral infection in the last month?
If you answered yes to any one of these questions, seek your GP’s advice before running.
*Lausanne Recommendations
