the younger you are, the faster your heart beats. geezers in their 50's top out around 154 bpm after grueling aerobic exercise.
An exercise program should include at least 20-40 minutes of hard treadmill or elliptical type workout; some bending and using weights, torso exercise with opposition or isometrics, and moderate weight movement, but usually not over 140 pounds for upper torso, or leg movements, and less for back bending.
depending on where you live, many communities have exercise rooms for its residents, where you can work out at a very reasonable price.
exercise regimens should be set at every other day, 3 times a week. if you incorporate the whole routine into one sitting, your workout will eventually go to about an hour and 20 minutes of so.
Now, if you have a heart problem, take a diary along and write in what happens during the workout- heart rate, pains, rhythm problems, etc., when, where, and under which stress. Vastly informative for your doctor. besides cluing in the doctor, if you have to have bypass surgery, you'll need every bit of stamina that your body can muster to get past the day of surgery and into a full recovery.