I guess I'm just a slow runner. I don't know if I'm not setting the treadmill fast enough but my heart feels like it's going to explode...and I'm not going that much faster than my regular jog. I ran 1 mile in 12.5 minutes today and walked 1.63 in 30 minutes. I guess I need to keep working on my strength training to get faster. Not sure how that will help my lungs though.