I use my HRM when running and on an easy days I'll range from 135-145. My max is somewhere near 195. I started last fall by riding my stationary bike over the winter months. I've been running for 3 months now and in the first few weeks I had a hard time keeping it below 160. It was frustrating having to walk when I wanted to run the whole time, but eventually I built up the strength to run longer. I've had a few days where the asthma gave me trouble and I needed my albuterol. Those were usually cold damp days. I use Advair and Singulair daily and also get allergy shots every three weeks so my asthma has been under control and doesn't seem to affect my running. At my last checkup I had a lung function test that showed improvement. My doc attributed most of it to the 20 lbs of weight loss at the time. So it can be done, it just takes time. I wouldn't worry about going too fast. MTA: Forgot to mention the months of riding bike in basement.