Hi Mary Ann - I don't have pulmonary hypertension, but I got really de-conditioned after a herniated disc problem followed by the onset of my connective tissue disease problems, and they both led to a very long period of not being up to much of anything. I finally made some progress this summer, and was up to walking 2 miles nearly every day. This was huge for me, because for so long - getting to the corner (we live in the middle of the block) was a challenge.
It will take time, so be patient. In fact, patience might be the most important factor. If you push too hard, you will burn out. Quit before you're tired, because, like your doc said, you still have to turn around and get home. I would turn around, and if I made it back to the house without being too tired, I'd walk a little longer, turn back, and repeat, even if it was only another 10 feet - but always stopping before I felt really fatigued. The neighbors probably think I'm a little nuts - but that steady increase without the anxiety of going too far, really helped me stick with it. I have also learned (from my husband and our dog) that pace and distance are not the only important aspects of walking. Enjoying the outdoors, and the nature all around (neighbors, too) is just as important. They like to stroll. And just moving beats being settled into the couch or the recliner.
Hope you enjoy a great weekend!!!!