I think it is interesting how many people who comment here state how active and healthy they were before PMR hit. I was the same at 71, doing uphill hiking, bicycling, yard work, gardening and birding carrying a telescope for several miles. No problems with blood pressure, cholesterol, blood sugar, weight, etc. But the year before I got PMR, 2020, I had substantial stress. My father died, expected at 103, but there was a lot of family disagreement and conflict. The pandemic hit, and a huge forest fire burned right up to the edge of the city, burned 400 homes, with smoke so thick it was impossible to go outdoors without a special mask for a week. My theory is that the COVID vaccine a few months into 2021 was the final straw. I've had overreactions to the flu shot for years, including fevers. The other factor regarding exercise is that I tend to overdo activity as a way to cope with stress and that adds inflammation. As we age we are less resilient. It's also interesting that people tend to get PMR in their early 70's and not at later ages. I think the immune system weakens and is no longer strong enough to cause the overreaction that brings on PMR.