I'm very overweight, 6'1, 142 kgs (313 pounds) 36 years of age. I had a work accident a few years ago and never really got active after and then I felt too "big" to exercise but I want to fight that mentality.
I also have asthma and I find sometimes that causes issues.
I have achilles tendinitis that can flare up occasionally. When I ran today, the balls of my feet hurt the most, and now as I sit, I feel sore all over (which I can work through).
I tried to run today at a track (just got a membership) and the most I was able to run was 200 metres without getting winded/feet aching beyond tolerance. I ended up alternating 200 metres jogging, then running, so I ended up doing 2000 metres at 26 minutes.
I have a goal of being able to run 4k in 20 minutes to start. Will it be possible for someone in my situation to be able to do this say in 90 days? What are some of the things I have to look at to prevent injury, etc?
Finally, I don't know how to swim but I'm learning. Will swimming as an exercise improve my ability to run longer distances? I have a friend in my swim class who runs 15km every morning but he gets winded very quickly swimming.. will the same hold true in reverse?
I've looked at questions such as: What should i do to run 6 miles in 1 hour
Edit: I'm going to keep track of my daily runs and will try to record my daily caloric intake as well.
Edit 2: I mentioned this in a comment but I figured I'd put it up here as well: This is the inspiration behind this effort: http://www.seattletimes.com/sports/seahawks/marshawn-lynch-saved-my-life-how-a-380-pound-man-went-beast-mode/
At 3 o’clock that morning, Jake ran about a tenth of a mile, walked another four tenths, and said he felt like he was going to die. The next day, he watched the interview another 30 times and did the same thing.
A couple weeks later, he could jog the full half-mile without stopping. A couple months after that, he completed a five-mile race.
Edit 3: Went for my second run. The pain on the outside of my feet is worse than the fatigue itself. Will try to get better running shoes (currently using Asics Duomax). However I do know that I have wide flat feet so I'm not sure what good selection there is for this.