@sjm46

Thanks for your input. After experiencing fatigue almost all the time I was diagnosed (Holter monitor for 24 hours) with afib (95%0 of the time. I was prescribed Metoprolol (a beta blocker) which was confirmed to eliminate the afib (Holter monitor for 24 hours) and did indeed feel much better and was able to walk and hike on mostly flat terrain for 10 miles with no difficulty. I tried a 9 mile hike with some climbing in it and ran into the extreme fatigue problem. Once that extreme fatigue started it did not stop. Then had a Holter monitor on for one month which showed no afib problem again mostly on flat terrain. I then tried a 10 mile hike and had another extreme fatigue problem. I assumed that somehow the afib was being triggered for some reason but it might be the Metoprolol which limits adrenaline to the heart which limits maximum heart rate and also limits pumping power. I now have another 30 day Holter monitor test starting in a few days to see what is going on. I will challenge myself with very many long hikes with climbing to try and recreate the problem. I am close to 77 want to live with as few limitations as possible. Two years ago we did Kiliminjaro and the Inca Trail. We have plans to do a Mt. Langley and Mt. Whitney night/5 day backpacking loop next year but this extreme fatigue initiated by climbing problem must be resolved.