I've been claiming that for years. Heart has specific numbers of heartbeats. I almost flunked highschool cause I never went to P.E. But on the other hand, I use my heartbeats for "other exercise"(mr. Bean meme here). But that's different.
Somewhat agreeable on the basis of the electrical systems of the heart. Problem is the ignorance here about muscle tissue and factors of cardiovascular disease. You may "waste" a few heart beats during exercise, but then again I could die tomorrow from a heart attack or stroke due to high blood pressure or cholesterol. You can buy yourself a few more years, but it's a gamble at best, under this logic. But the American Heart Association has been doing research on that for years. Why would we trust leading medical experts when we can find faulty logic that makes us feel better about ourselves.
Kinda make sense but also doesn`t. The heart is a muscular organ so if you do increase your heart rate by exercise you working it out and making it stronger like any other muscle. If you compare it to a car, the faster you drive the car the more wear and tear it takes and it cannot replenish itself like a living tissue i.e muscle. Just my opinion :)
'Doctor, is swimming good for my figure?'
'If swimming is good for your figure, explain the figure of a whale to me.'