Learn something new, everyday . To be happy, most of us must also be growing, expanding, learning and challenging ourselves. Read, listen, adapt and stretch to accommodate new ideas and new information. Use your body as it was intended . Walk and run, stretch, throw things, and lift things.
Exercise is good, but so is making love, mixing up a batch of cookies, or exchanging backrubs.
You have a body and it can be either a source of joy, or a source of aches and pains. Avoid toxins . Avoid poisons whenever possible. It seems to work out better that way.