I am a 50-yr old female long distance cyclist and have known for years that I am at risk of osteoporosis because of the long distance cycling. Evidently it saps calcium and since it is non-impact, it does nothing for bone density.
So I started walking. I cover a minimum of 1000 km/year of walking in addition to my cycling. And quite a lot of that has been walking while carrying a heavy backpack going to university and elsewhere.
Walking is an impact exercise and is supposed to help build bone density.
I also do some weight lifting and have recently started running.
But my cycling hasn't changed ... it did ease off a few years ago for various reason (DVT, travel) but I've been building up the distance and quantity again.