To not give your best is to sacrifice a gift is saying by Steve Fontaine. Many activities can be done to the best I tried some of them. For example cardio/resistance a new fitness trend where you can do and switch between cardio workout with resistance intervals . But honestly those should be left for healthiest individuals. By the way anybody between ages of fifty five and sixty five should have a physician present during training. Those are the guidelines. And by the way fitness is rewarding in many ways and one of them is self-esteem.