For starters, I am 75 years old and no Jack LaLanne when it comes to exercise; however, I believe that his approach to exercise--"motion is lotion, rest is rust--hits the nail on the head with surgical precision. My first rule is "don't get injured". I approach all the physical activities I engage in with that in mind. Much of exercise at my age is minimizing losses--muscle loss, bone loss, strength loss, and the rest. Yet with resistance training, balance exercises, flexibility exercises, and cardiovascular training, I am able to do quite well at holding off the kinds of things that plague seniors. Just as important as exercise is good quality sleep, stress management and nutrition. I like variety, and so change things around regularly. My latest old-dog-new-tricks exercise is learning to juggle, which is fun and helps eye-hand-coordination, reflexes, balance and cognition.