I was out backpacking last week and find that my stamina is really low. I will turn 75 this year so perhaps it is just getting old. I also had a stroke last year (PFO) but no noticeable damage. I also have COPD from spending a life time welding, grinding painting and smoking when I was young and foolish. In the past I could pretty much maintain 2 MPH but last week I was having trouble with 1 MPH. I would walk 500 feet and my legs would feel fatigued. Walk 500 ft, stop 1 minute makes for slow going.

I am right in mid range for weight, blood pressure is good, all other blood work is in the proper range.

I have been using the treadmill 30 minutes per day at 3 1/4 MPH 4-5 days per week and that goes just fine (other than boredom). Surprising but I do not feel the same leg fatigue when using the treadmill.

I am just fine with the slower pace but the leg fatigue gets rather unpleasant.

Any words of wisdom from other old farts? Something else I could or should be doing?

I bought a camper this year and I have been parking it in state forest campgrounds and hiking out and back one day and out and back the other direction the next day. This removes the pressure of must be at a goal for water, pick up etc. It is nice sleep on a bed and have real food but I also would like to do some backpacking.