There have been quite a number of cases where athletes participating in sporting events and NSFs participating in route marches experience sudden cardiac arrest.
Both young and old fell victim to sudden cardiac arrest, even those that seemed to be fit. Just goes to show, that you should be prepared.
As a coach meeting people of various fitness levels and age in the courses or activities I conduct. So...
Its a good skill to have, especially when all Water-Venture outlets are equipped with an AED. Doesn't hurt to be prepared.