What you don't want is severe pain. If you don't feel like exercising at first, it will be easier the second time. Exercises that are good for seniors to try are lifting weights, stretching and walking. Weights do not have to be heavy to be beneficial. Every time a senior gets up and does something, they should give themselves a hug for doing an activity rather than sitting.
Simple stretches are helpful.
Stretching will keep muscles limber and if this form of exercise is handled easily, a yoga class is good for gaining more flexibility and freedom of movement. Stretching by nature is relaxing. By easing into it, there is no real pain. Tony Berryman, a registered massage therapist in Vancouver, B.C., suggests minimizing distractions and concentrating on what you are doing and what your body feels. This will make the stretch session turn into an exploration instead of a dreaded chore.