Dr. Andy Galpin

We really can't change the contractile properties in the heart, especially acutely.

What we can do is put it on more stretch.

This means more blood back into the system.

Again, preload, we'll talk about that a little bit later.

Afterload's another way.

But if we put more back into it, we put the muscle on a bigger stretch, and this allows it to then respond.

I'm thinking about like a rubber band.

If I pull it a little bit, it snaps back.

If I pull it a lot, it snaps back harder.

That's all we can really do.

But it is not meant to be regulating force up and down.

We don't even have motor units.

It's an all or none thing, ideally.

And so we've got a lot of mitochondria in there.

We are phenomenal at aerobic metabolism.

Again, specifically within the contractile properties, we're not talking about aerobic metabolism of your entire system or heart.

We're talking about the capillaries surrounding the heart itself, the ability to get blood through.

into the tissue of the heart, not the blood actually in the chambers that you're using to send the rest of your body.

Remember, your heart has its own blood supply, not the stuff it's trying to give out to everybody else.

Think of this like as Halloween, where you're sitting in house and you've got this giant bucket of candy and the candy you're giving out to the rest of the world.