Smigman

I'm 46yr old blk male, six months post-op stent surgery on RAD and scheduled to have a stress test with cardolite in 2 weeks to check my progress.  I'm also recently (within the past 8 months) discovered I'm diabetic with BPH problem. I started an exercise program last summer of walking which led to lite running, weight lifting and now cycling (to take the pressure off the ankle and knees). I've lost about 75lbs over the course of this time, currently 6'2"  235.   I'm averaging about 80 to 100 miles a week cycling.  I feel somewhat ok, just anginas here and there from time to time and some heaviness in chest and  just feeling uncomfortable, nothing major and very infrequent.  My questions deals with exercising:  How much is too much?  Heart rate, what should I try to maintain when exercising when to back off?  Also, just what should a person be feeling at this point of recovery?  I have a stressful job (fire fighter) and I'm pushing myself more with exercising where by I'll be able to handle my job easier and take stress off my heart, I think thats working, but I think I'm right on the edge of doing too much, which might be leading to the symptons stated.  I want to push it harder but safely.  Right now I'm in the best shape I've been in 15 years but not feeling all that great.  I'm currently taking plavix, coreg, proscar, avalide, aspirin, metformin and multi-vitamin. Thanks