Race car drivers don't have to be in shape, but they have to pay attention to every detail and push their vehicles just to that limit. If they don't, they lose, if they go beyond they could die.
http://www.tfproject.org/tfp/showthr...threadid=60295 check that thread for reference.
Baseball isn't even close. Besides hitting, which is extremely difficult, the running isn't that difficult, the catching isn't that difficult unless you're going for a catch only pros make on a regular basis, and the running is far less than that of other sports.
I think a triathlete should be disqualified just because it's just mindless competition. There's no strategy, it's just go out and swim, go out and ride a bike, go out and run. A race car driver on the other hand posesses a lot of skill and uses a lot of strategy, especially in compairison to a triathlete.
Hockey is still top in my opinion. First of all it's on skates, which is difficult enough for some people. Then throw in controlling a puck in traffic and it becomes much more difficult. Throw in the pure physical contact and the different strategies and positioning and the skill required of the goalies and it has to be number one.