53, just wear and tear. Never felt any one thing. Had it looked at a few years back and doctor said repetive use. Pushed too hard when I was young. When I was young and doing ground work I'd run with with small logs or blocks of wood on my shoulder. Had to lift the most and be the fastest. Thought my body was made of steel. Tried to live up to the way my Dad worked. At 79 he still had bi-ceps the size of grape fruits. He died of prostrate cancer at 81.
When my Dad retired I let the business go and went to work at UPS, for the benifits and 8 weeks vacation. I kept my license and insurence, because I enjoyed climbing so much. I worked most every weekend and most of my vacations any way. I took that same mentality to UPS, had to do the most and be the fastest. All the running and jumping on steel and concrete is what really did the damage. I loved to climb to relax,and I guess that's not the best way to let your body rest and recover.
My Dad climbed into his 70's. My cousin is in the tree business too and one of his top climbers is 62, I think. I know he's over 60. Another one is 55 and prefers to throw a johny ball through a crotch and pull himself up 40 or 50 feet rather than get a ladder out.
If longevity is your concern, you can do it, just take care of your body. You can walk with a sense of urgency, you don't need to run. Don't work every weekend, rest up.
I essentially worked two jobs and made good money. With my UPS pension and savings from side work I'll have a real nice retirement, but I'm kinda beat up from it. I just went on a 10 day wilderness hiking/camping trip with my son. We hiked well over 80 miles at over 10,000 feet. I was the oldest adult on the trip and I was still the first adult to the top of 3 of the 4 mountains we climbed. It's just that the fun of climging is no longer worth the pain. If I still needed to climb to make a living I could do it, I'd just be slower. If I had taken better care of my body it probably wouldn't even be an issue. Take care and keep climbing, Joe.