66 here. my cardio is in pretty good shape from 3x/week or more spin class, an hour at a time. And weights. But I've found that unless I specifically work my adductors to exhaustion, they easily get inflamed on an elk trip. And last year's elk was shot about 8 days after I quit testing positive for Covid, and I had no energy. The good news, it was a short pack out over an icy hill. The bad news, I was bog slow.