Exercise and heart problems

I am 61 with probable angina and have recently started exercising at the gym.  I have hypertension and raised cholesterol, controlled by medication.  Most of the time I try to be sensible, keep my monitored heart rate below 145 etc. but occasionally I really want to push myself to see how much I can do (treadmill, cycle, cross-trainer).

If I do push myself to the limit of getting pain, is there any risk of long-term damage?  I've only twice had any minor pain at the gym, but two weeks ago I ran for a bus and had severe pain radiating into my neck which took 25 minutes and 3 doses of GTN to clear.  Nothing major since, though.

How often should I be exercising?

[Cleveland Clinic]

You can exercise as many time as you want but do not reach the chest pain threshold.  there is a risk of low oxygen supply to the heart which may result in a heart attack or a lethal arrhythmia.  I would not push myself too hard.    

[Healthyself2]

I had a heart attack 8 years ago, have a 100% occluded RCA, a ruptured plaque in my left main, and well progressed 3 vessel CAD.

Today, I feel that my disease is in total remission.  Didn't have bypass or stenting, just have taken an agressive cocktail of lipid and BP meds and practiced long duration low aerobic exercise.

If you have angina, I believe that it's extremely risky to engage in any high aerobic activity, especially if you have untreated lipidemia where wet plaques are likely to burst or leak.

I practice long duration mildly aerobic exercise, mainly hiking and skiing moderately.  I'm a total believer and living proof that long duration exercise is the key to developing cardiac perfusion.

After my heart attack, I had a very low angina threshold.  If I pushed through it, I paid with inflamatory pain around the heart.   I learned where the threshold was and pushed up against it every day, walking uphill, but was careful not to push through it.  Over time my ability increased.  Today, I can't remember the last time that I experienced angina, but am sure that I could if I did something with enough aerobic demand especially if there was a high degree of fear or stress associated with it.

Last Friday, I hiked 12 miles with a moderate 2,000' elevation gain.  I was surprised that I had no angina or residual inflammatory pain in my chest, as my dietary and alcohol habits have not been great in the last few years.

Bottom line is treat lipids agressively and practice long duration low aerobic exercise daily.  A treadmill won't keep you interested.  Get out the in the real world or move to the mountains like I did.

Good Luck