Peter Attia

So what you could sustain for five to 10 minutes.

Obviously, there are so many gradations here.

Your functional threshold power, which is what you could obtain for an hour, is obviously smaller number than the peak and a shorter number than the base.

So anyway, the goal here, if you're trying to maximize your total aerobic capacity, is to maximize the area of this cardiorespiratory triangle.

And of course, to do that, you want to have the widest base and the highest peak possible.

And these require different forms of training.

So if you just trained at one intensity level the whole time,

you would increase both of these things.

I want to be clear on that point because it creates so much confusion.

If you only parked yourself at one level of training, you would, through enough volume, increase both of these.

But that's not the way to maximize the problem, and it's certainly not the most time efficient way to do it, nor is it necessarily the best way to do it.

In fact, it's almost assuredly not, given the fact that no high-level athlete trains that way.

The base is ideally built through adaptations that help you utilize oxygen more efficiently to convert fuel, but mostly fat, into ATP.

What this is really geared towards is improving mitochondrial density and efficiency and optimizing fat oxidation and lactate utilization.

Conversely, the peak, which again is that VO2 max, represents the ceiling for oxygen delivery primarily, but utilization

And it's driven by how well this system can deliver oxygen to the mitochondria.

That's primarily the bottleneck.

It's how much oxygen can you deliver to mitochondria versus the base, which is how much can you utilize substrate efficiently.

So when it comes to delivering oxygen to the mitochondria, there are really four big drivers.

There's the diffusion of oxygen from the lungs into the blood.