Last September, four men taking part in the Great North Run died unexpectedly. Though the coroner's inquest continues, the cause of death is thought almost certainly to be Sudden Adult Death Syndrome (Sads), often called 'adult cot death'. Sads can happen at any time though is much more likely during physical exertion.
To the uninformed reader, deaths during marathons and sport in general might seem to be reported more often now; the death of the Cameroon footballer Marc-Vivien Foe during a match in 2003 sticks in the mind. But does this mean they are happening more often?
David Hart, communications director of the Great North Run, says: "Eight people had died in the previous 24 years, so for four to die (last) year is a tragedy."
And it seems, despite the day's unseasonably hot weather, a coincidence. Men are statistically more at risk than women, not just because men tend to exert themselves more.
Hart adds: "The 12 people who've died (in the run's 25-year history) have all been male, despite male-female participation being 50-50."
Dr Dan Tunstall Pedoe, joint medical director of London Marathon and author of Marathon Medicine, reports that in 25 years of London Marathons, about one in 65,000 runners has died, roughly one every two years.
"You are more likely to be killed riding a motorbike for the same amount of time," he says.
Even so, according to the charity Cardiac Risk in the Young, every week in the UK eight apparently fit, young people die from undiagnosed heart conditions. So what causes theses deaths and can they be avoided?
There are essentially two types of sads. Both are related to the heart but one applies to under 35-year olds, one to older people. Tunstall Pedoe says: "In the young, sudden death is caused by a variety of symptoms; for older people the causes is overwhelmingly coronary artery disease."
The 'variety of symptoms' in young people tend to be congenital abnormalities. The most common, the one that killed Foe, is hypertrophic cardiomyopathy, a thickening of the left ventricle. These various ailments cause abnormal heart rhythms, which might cause the heart to stop pumping blood, leading to sudden loss of consciousness, followed, if not corrected, by defibrillation or cardiopulmonary resuscitation (CPR), by death.
The value of screening the young for potential causes of Sads, using an electrocardiogram and family medical history is debatable, according to Turnstall Pedoe. It's expensive, not 100 per cent effective and produce false results. Sads is caused by a variety of conditions, not all of which are tested for, and is very rare – a US test of 5,000 children found nothing. Funds could, perhaps, be better used elsewhere.
However, Alison Cox, founder and chief executive of CRY, thinks that children should have "an ECG with their BCG (anti-tuberculosis vaccine)".
Dr Sanjay Sharma, joint medical director of the London Marathon agrees:
"We've run tests at Eton, Millfield and Worcester College bi-annually and we've picked up four of five problems that have been rectified, which is four of five lives saved, as far as I'm concerned."
The experiences in Italy back up the pro-testers. Sads screening is compulsory for county level athletes. It seems to have worked. In Italy, after screening, hypertrophic cardiomyopathy causes only 4 per cent of deaths, in young athletes. In the US, it accounts for a third of all young Sads deaths. It's possible, though unlikely, that this is for other reasons but if so these have yet to be discovered.
Once screening uncovers a Sads-causing ailment, further testing analyses the seriousness of the problem, then the sufferer's exercise regime is limited accordingly. It is possible to fit an internal defibrillator, which starts when abnormal heart rhythms inhibit blood flow.
In the event of a Sads attack, Dr Robert Campbell, medical director of Sibley Heart Centre at Children's Healthcare of Atlanta, says the key to preventing death is "CPR and defibrillation within three to five minutes of arrest. (These) are the keys to secondary prevention of Sads."
Read more about Hypertrophic Cardiomyopathy (HCM)
