You need to talk "life plans" with the doc's based on their expert diagnosis. I had a -4.0 on my bone scan over 5 years ago. I get Prolia shots ever 6 months, take Calcitrol tabs daily and OTC calcium supplements for my bones. I also like to be active and do things. My last bone scan around a years ago showed -2.0. So things have improved!!! I don't do as much exercising as you sound like you do but I am 68 with my second organ transplant over the past 24 years. My problem seems to be tied to calcium absorption. The doc found I had parathyroid diease. I had surgery to have one of the 4 parathyroids removed in 35 min surgery. That has helped too.