This government site is terrific if you are looking for some exercise that is good and safe for older adults. Titled, "Growing Stronger - Strength Training for Older Adults: Introduction," and part of the Centers for Disease Control, it's well worth checking into.
The site begins:
"Welcome to Growing Stronger: Strength Training for Older Adults! If you're interested in feeling stronger, healthier, and more vital, this program is for you. This strength-training program was developed by experts at Tufts University and the Centers for Disease Control and Prevention (CDC)."