It's so incredibly sad, but you never know what the circumstances are, and you never know when your card's marked
Statistically, I've read that there will be something like one death per marathon from every 800,000 hours of running from a cardiac related symptom - the figures go down the shorter the race is. For the London Marathon, the stats show 1 death for every 2 million miles run.
Isn't it a strange thing that it's always men who collapse and die at these events, I can't remember hearing of a woman (and research suggests men are much more likely to suffer heart cell death during endurance events).
It often turns out that there was a pre-existing condition that the run just triggers (heart condition/abnormality/other) I'm wondering if it could have been hyponatremia related - it was a hot day, perhaps he took on a lot (far too much) water - hopefully we will find out to put minds at rest that running isn't generally dangerous.