Originally Posted by Hosscooper

… For a 50% workout it should be closer to 135bpm. Should I back off and…. .

So who told you to keep it at 50% and why?

My cardiologist and exercise physiologist are telling me to keep my heart at between 75% – 85% of my max.

I am NOT saying that 75-85% is the right number or that 50% is the wrong number. But, there are many theories on exercise heart rate and many of those theories are based on what the goal is: Enhance performance, lose weight, increase endurance, improve endothelial function, etc…

I AM saying that the whole subject becomes very complex with no clear winner take all answers…

I am also saying that it is worthwhile to try to understand some of those issues and concepts and do your best to apply them to yourself. There are many on this forum that are very knowledgeable on this area and can lead you to the best resources… (Unfortunately, I am not one them! I am very much a beginner).

But, the one piece of advice everybody seems to agree on is: Any exercise is better than no exercise (unless your already dead).