I don't think anyone has good data on sports where events last >10 hours. The population of athletes is quite small which makes it difficult to study effectively.

There is a bit more data on iron-distance triathlons, where the elites finish in the 7-8 hour range. They all do some high-intensity interval workouts and none are on ketogenic diets. Whether this type of training and racing is optimal for overall health and longevity is an open question; I suspect probably not.