Dr. Andy Galpin

That would mean your stroke volume would need to be somewhere in the area of about 80 to 90 milliliters.

All right.

Now, for some of you, depending on where you're at, milliliters make complete sense.

Those here in America, maybe not.

And so I've converted that at something in the neighborhood of like, you know, just under three ounces.

And so while you're sitting here resting, every time your heart is beating, it's kicking out about three ounces of blood every time.

Watch how high this number gets when we get to maximal exercise.

In the case of these phenomenal athletes like Paula or Oscar, we don't actually know their stroke volume, but we can run some quick calculations and get a pretty close estimate.

Oscar would have had to be in the neighborhood of about 225 milliliters at his max to reach the cardiac output of around 40 to 45 liters to give him a VO2 max in the 100 or so milliliters per kilogram per minute.

Again, I know I'm moving from liters to milliliters, so run the math yourself if you want to challenge that number.

On the back end, as I said, AVO2 difference is really kind of complicated.

So most people are probably in the neighborhood of about 70% extraction rate.

So of all the oxygen going into tissue, they're able to get about 70 of it.

Higher trained athletes, though, are looking something more like 93, 94, 95%.

And so the ability to extract, get it into tissue is just far higher than the average person in that 70% to 80% range.

Coming backwards into stroke volume, if we assume that he or she is in that neighborhood of like, you know, 200 to 225 milliliters or so, this is what that math would look like.

If we said Oscar was, call him 20 years old to make math a little bit easier, his predicted maximum heart rate would be about 200 beats per minute.

If you're not familiar with that equation, if you take 220, subtract your age, and that gives you a very rough, and please, this is just a rough estimate of your maximal heart rate.

But a maximum heart rate of 200 beats per minute is maybe a little higher than what you'd really see, but not out of the question.

So if we took 200 and multiplied that by 225, that stroke volume, so heart rate multiplied by the stroke volume, that would put us right near that 45 liters per minute mark.