“Monotonic Convergence” is why aerobic exercise is bad for you. Now, I admit, I made up that term; adapted it from my background in math. Still it tells the story even if in a coded kind of way.
You see the healthy heart is a restless heart: it goes fast, it goes slow, it stops, yes, I said stops, it jumps all over the place. It responds to thousands, well millions if you want to know, of signals every single second. And a healthy heart adapts to those signals very precisely. Its ability to adapt, to speed up and slow down quickly and for that rate of change to be entirely driven by coherent integration of information is the hallmark of a healthy young vigorous heart.
When you do aerobics, when you jog, when you get on the treadmill and grind out a few miles for an hour or so you train the heart to beat at a nearly constant rate; very little variation and soon the heart ‘goes to sleep on the job.’ You train out of it the exquisite attention to detail that is its greatest strength. Eventually conventional aerobic exercise yields ‘monotonic convergence’; you are dead. It is a demonstrated fact that regular marathon runners have an accelerated rate of developing ‘hardening of the arteries.’ That is the perfectly appropriate old-fashioned name for atherosclerosis.
A large number of runners have bragged to me that they are so ‘fit’ that they can barely get their heart rate up. They imagine some Ferrari of a heart that needn’t work very hard to cope with the stresses we mere mortals demand of our hearts. Nice head picture; not actually very nice. That is a sign of an inadequately challenged heart; one that doesn’t recognize the minute exquisite demands to which it is to respond.