There are some studies on dogs without many results. Sedentary is bad, but exercise beyond that doesn't seem to boost lifespan in most (any?) mammals. Maybe humans are different, we are the best endurance runners of all animals and one of the few that cool by sweat.

Re: healthspan there is injury risk from exercise too but if it really prevents hip injuries that well that is a good point. Intense exercise definitely seems to be important for astronauts, but also is sort of just barely getting to the level of sedentary on earth and I think they still lose bone density.