As someone said: This came up before. however this is interesting to this group of 50+.
I hike a lot including rock climbing. Problem is that this causes its own problems with wear and tear. Jogging is not good for 50+ as we all know.
Swimming is great if you have the opportunity. Kayak is great for upper body. Nothing is perfect.
Biking is great for CV and attitude. Not great for bone density.
Doing nothing is the worst. I do not like to talk about all the friends I know who suffer the consequences of inactivity.
The trick is to find balance in life. Greater people then me have said that.