I would guess it depends on the person, the level of fitness, and the type of meds. When I started exercising, doing 3 mph on the treadmill was challenging and I couldn't work out for more than 10-15 minutes. Now I can actually run at 5.5 mph. Having my heart rate in the 150s for short periods is challenging but I don't get dizzy, sick or anything. I am 55 but I think that building up over time, and working with a trainer, really can help. I also managed through all this to lose about 40 pounds.

I do spinning classes, trainer rides, ride with the club, and do 5K walks (races) as well as working out on the treadmill. I also like yoga but I have to be careful with strength training. That is where I can develop real problems.