HAVE YOU EVER wondered how your favorite types of exercise stack up against one another? In a new study—to be published in Medicine and Science in Sports and Exercise—scientists sought to find out what exercise is best for amping VO2 max.

VO2 max is the maximum amount of oxygen your body can use in a set amount of time, and it’s dependent upon how many red blood cells you have, how adapted you are to endurance activities, and how much blood your heart can pump. Essentially, your VO2 max is a measure of how fit you are, so, yes, you want to improve your score to become more economical in your sport (whether you’re a runner, cyclist, CrossFitter, or something else)—so you can do whatever it is you do faster and with less effort.

We already know interval training is among the best ways to transform your physique and blast fat, and steady-state cardio is necessary for creating a training base and making our bodies more efficient at using stored fat, but what’s the best way to increase VO2 max?

Researchers recruited 30 overweight and obese subjects ranging in age from 32-50, and put them through three popular exercise modalities. They were randomly selected to complete six weeks’ worth of:

1. High-intensity interval training which included 4 sets of 4-minute high-intensity intervals on a treadmill at 85-95% of their maximal heart rate with 3 minutes of rest in-between each interval;
2. High-intensity interval training which included 10 sets of 1-minute high-intensity intervals on a treadmill at their VO2 max load with 1 minute of rest in-between each interval;
3. 45 minutes of moderate-intensity continuous training on a treadmill at 70% of their maximal heart rate.

Their time to exhaustion, vein and artery function, blood volume, and calculated stroke volume levels (the amount of blood pumped out of the heart) were measured before and after the training period.

As you may have guessed, the 4×4 minute HIIT increased VO2 max the most—and significantly more so than the 10×1 HIIT exercise group. The former boosted VO2 max by 10% and the latter by 3.3%. The moderate continuous slog group came in dead last, though still increased V02 max by 3.1%.

Here’s another reason to hit the track and truck through some intervals. Check out these workouts for some ideas and inspiration.