Practising Cardiologist and author Dr. Warrick Bishop explains when too much exercise can put strain on your heart and the difference between isotonic and isometric exercise.
In my practice as a cardiologist, many of my patients are unaware that not all types of exercise are created equal. It turns out that some exercises are better than others... http://www.drwarrickbishop.com/
You may be surprised that fitness is no guarantee of heart health and that arteries in your heart are in good shape. For instance, in recent years, I had an extremely fit patient come to see me for a stress test. At that time, he was training for an endurance event and by all accounts, he was in fantastic shape. Several years earlier we had scanned his heart and we found that he had a build-up of cholesterol in his arteries for which he was already receiving therapy.