What is most toxic to seniors are falls. That is because of muscle loss due to low protein intake and a lack of resistance exercise.
Seniors' need for protein goes up every year! Women are slightly more prone to falls than men because muscle mass may be lower to begin with. 9NPR)

So more important than cardio training is resistance exercise. More plant or meat proteins are needed with the increase in age.
Muscles- 'use it or lose it'. We have seen the last incident of catters have been falls or at least more frequent falls.
A simple solution is a 10 minute stair climb program. Impact with the floor is also good for bone density.

It sounds like this post can be ignored by Stilly. The protein thing surprised me.