In reply to lansa:
Hi Ian
Sorry to hear this - join the club.
Unfortunately it's a double whammy: the cancer cells substitute for healthy bone and weaken it, and the hormones also demineralise the bones and weaken them. At end stage, we will be breaking ribs turning over in bed - the bones will become very, very fragile indeed. Furthermore, healing is very much impared - it breaks; it stays broken.
In healthy people, operating bones under load is generally a good thing and helps keep the bones strong - for example, it's a core part of most rehab for broken legs. So a sliding scale from where you are now.
The other issue is what bone you might break. A wrist can be splinted, but pelvis or neck of femur would be a sentinel event.
Unfortunately prostate cancer has an exquisite affinity for bone, and the most common are pelvis and spine. Fractures in these can be very very serious - hence your consultant's caution.
So where does that leave you? You are 81 - and might hope to get a couple of years out of the hormone treatment, or even more, before the cancer becomes castration resistant. After that chemo will make you sick and give a few months here and there.
You might decide that pottering gently doing something you love at that age is worth it...
I'm staying off treatment for as long as possible (even though it may shorten overall life) precisely because of these side effects. I'm 54.