Dr. Andy Galpin

But the length is very, very short.

Now you're talking about something like 0.1 centimeters in length.

And the reason we want that, or the reason that actually is happening, is because the fibers themselves are what are called single nucleated.

And so this differs significantly from skeletal muscle that has thousands of nuclei in the cell.

The nuclei, as a quick reminder, are the place in which you hold your DNA.

It is the control center of the cell.

It determines how the cell responds to external stimuli, recovers, repairs.

It goes through protein synthesis or adds more mitochondria, deletes them, or whatever the case may be.

This is being run by the nuclei.

And so by having more of them in the skeletal muscle, it allows it to be extremely plastic and adaptable and responsive to exercise or interventions or lack of exercise or anything else going on.

I don't need that.

and cardiac tissue.

In fact, I don't need it to be growing and shrinking and dying really quickly.

What I need it to be doing is extremely consistent with both its activation, so its contraction, and the force applied in that contraction.

So the fact you've got a single nuclei in the cardiac tissue tells you its primary role is not actually adaptation.

In fact, depending on the study you look at, you're going to see that the muscle fibers in your heart

are gonna turn over somewhere between 50 to maybe up to 70% throughout your lifetime.

Meaning many of the fibers in your heart that you have as a child, especially past puberty, are gonna be there the rest of your life.

There isn't a huge turnover.

Now, that differs considerably if you look at something like the skin.