Yoga is safe for the elders, and power walking was made for them. You would need Growing Together to see power walking though. And they can hike in Granite Falls and Mt. Komorebi.
I moved a sim in with the Charm family once (Realm of Magic). There's a weight machine in Darrel and Emilia's room. Poor old Minerva kept using it, and then randomly getting either embarrassed or angry and dying. I think I brought her back 4 times! Between that, and that you have to fix her so she can pee-- that poor lady! (She is somehow missing the hidden trait "Toilet use sitting." You can cheat it on using MCCC, or cas.fulleditmode and in CAS, go into custom gender options and change "Can this sim use the toilet standing?" to "Yes" and then back to "No.")