Why runners with higher VO2 max lose to lower numbers

HostWe often hear about these big numbers in pro sports, especially in running. There's this one score, the VO2 max, that people treat like a high score in a video game. It measures the most air your body can use at once, and the logic goes that the higher the number, the faster the athlete should be. But then you watch a race, and the person with the massive lungs and the perfect score gets beat by someone with a much lower number. It feels like the math of the sport is broken. Why is that number not the whole story?

GuestIt helps to think of that number as just the size of your engine. If you have a huge engine, you have the potential to go very fast, but an engine on its own doesn't win a race. You have to look at the whole car. A big engine in a heavy truck with flat tires is going to lose to a smaller engine in a light, sleek race car. In running, that sleekness is what we call running economy. It's basically how much energy you waste just to move forward. Two runners might be going the same speed, but the one with the better economy is using less fuel and less air to stay there. They don't waste energy wiggling their arms too much or bouncing too high off the ground. They're like a car that gets great gas mileage, while the runner with the big VO2 max might be a gas guzzler. If you're wasting effort with every stride, it doesn't matter how much air you can pull in because you're just burning through it to stay in place.

HostBut if I have a massive lung capacity, can I not just afford to be a bit wasteful? If my engine is huge, I have more air to burn than the other guy.

GuestYou would think so, but there's a hard limit to how much of that power you can actually use for a long time. This is where we talk about the red line, or the lactate threshold. Your VO2 max is the top speed the car could ever hit, but you can't drive at top speed for an hour. You would overheat. The threshold is the highest speed you can keep up without your muscles filling with that burning acid feeling. A runner with a lower VO2 max might be able to run at ninety percent of their top speed for a long time, while the runner with the bigger engine might start to feel the burn at only seventy percent. Even if their peak is higher, their steady pace is actually slower. They have a big tank, but they can't open the tap all the way without the whole system shutting down.

HostThat's a bit of a shock. So it's not just how much air you can take in, but how close to the limit you can stay before the pain kicks in. But does the way you actually move your legs change the math, too?

GuestIt's huge. Think about a bouncy ball versus a piece of clay. When a bouncy ball hits the ground, it pops right back up. It uses the energy from the fall to move again. Your legs are supposed to work the same way. We have these long cords in our legs called tendons that act like springs. Some runners are just better at using that free energy. They land, their springs stretch, and then they snap back. That's free power. A runner with less springy legs has to use their muscles to push off the ground every single time. That takes a lot of air. You can have the biggest lungs in the world, but if you're working twice as hard to get off the ground because you lack that spring, you're going to tire out much faster than the person who's basically bouncing along the path.

HostI never thought about it as free energy. It's like the difference between a high-end sneaker and a heavy boot. But even with the springs and the red line, there's still the mental side. Does the brain ever just decide to quit even when the numbers say the body is fine?

GuestThe brain is actually the boss of the whole thing. There's a common idea that your brain acts like a governor on a car engine. Its main job is to keep you alive, not to help you win a medal. It's constantly checking your heart rate, your heat, and how much fuel you have left. If it thinks you're pushing too hard and might actually hurt yourself, it starts sending out those signals of extreme tired feelings and pain. It makes you slow down long before your body actually fails. The thing is, some people have a brain that's a bit more relaxed about those limits. They can push closer to the edge. A runner with a lower score might just be better at convincing their brain that they're not actually dying. They can hold that red line longer because they can handle the mental stress of it.

HostSo you could've a runner who's technically a better machine on paper, but their brain is just more cautious.

GuestExactly. And that caution changes based on the day. If it's hot out, your brain will pull the plug way earlier because it's worried about you overheating. This is why a runner can look like a world-beater in a lab test on a treadmill but then fall apart on a sunny day with hills. The lab test only looks at the engine. It doesn't look at the springs, the weather, or the person driving the car. The winner is usually the person who can do the most with the air they have, rather than the person who can just move the most air in and out.

GuestResearchers now think the real secret to winning is how the brain learns to ignore the body's frantic screams to stop.

HostThe math on those test results looks simple, but the actual race is won by the person who can squeeze every last bit of work out of a single breath.