Could your decreased capacity for breathing have something to do with your heart @GP44 ? My mother never smoked or did anything considered unhealthy, but when she developed Congestive Heart Failure she spent the rest of her life on oxygen. As others have said, it is best you see a doctor to try to ward off further complications.
I have a close friend who is 63 and is very physically active. He was starting to get short of breath on his hikes. A specialist said his arteries were only at 60% and he just underwent open heart surgery. He had the surgery in November and was traveling again in January. Oddly, his 67 year-old brother just underwent the same surgery. The doctors seem to think it was caused by their diets when they were younger.
I have a close friend who is 63 and is very physically active. He was starting to get short of breath on his hikes. A specialist said his arteries were only at 60% and he just underwent open heart surgery. He had the surgery in November and was traveling again in January. Oddly, his 67 year-old brother just underwent the same surgery. The doctors seem to think it was caused by their diets when they were younger.