Running progress

I always hated running. I was the kid huffing and puffing during runs at school, and looking for any way to get out of doing it. I was the one getting winded after running 30 sec. for the bus. Up until a couple of years ago, I also had a weird knee issue (cavernous hemangioma) that made any exercise involving my quads painful. Now, I'm officially registered for my first 5k run in mid-Oct. I've started training using the treadmill. I find it keeps me more focused and disciplined than running outdoors, and I also feel more secure when I can monitor my heart rate. I quickly figured out that running raised my heart rate FAST, and can easily put it way beyond the upper end of my target heart rate. The first time I realized this, it was hitting 170. No wonder I had the "I'm about to die" feeling. I'm now figured out that in order to keep running without too many walking breaks, my pace needs to be slow. Very slow. 4 miles/hour is my new pace. Part of me wants to go faster, but at 4 m.p.h. I can maintain a jog for a decent amount of time without getting completely out of breathe or wanting to collapse. Last night I managed to do the 3 miles in 46 min. - I know that's really slow for a runner, but it's huge for an absolute beginner like me. I also enjoyed a nice endorphin rush. Looking forward to seeing that time drop as I'm able to slowly increase the pace. 40 min. by race day would be nice.