What most naturally follows?

How to stay fit after 50
Join a gym.
When you're over 50, it becomes more important to ease into new physical activities. Your body simply can't handle abrupt changes and extreme activities in the way that it used to.
Joining a gym is a great way to start a new exercise program because you'll have access to a network of professionals. Look for a gym that offers a free personal training session and health consultation for new members.