Exos | Formerly Core Performance

Set Your Fitness Goals. We'll Help You Achieve Them.

Join for free and you'll gain instant access to our tracking and reporting tools, expert coaching tips, and a free trial to our personalized training and nutrition programs.


The Performance Life

So What Exactly is VO2?

Jeff Vinnick / Getty Images

For many endurance athletes, there’s perhaps no more confusing topic than V02 max. Most understand that it’s the gold standard for cardiovascular fitness. Beyond that, well, it gets a little confusing for the layman.

What it Means

“V02 is milliliters of oxygen per your body weight per minute that you can move or utilize,” says Paul Robbins, the metabolic specialist for Athletes’ Performance. Simply put, the higher that number, the more cardiovascular strength you have.

The numbers vary by sport. Major League Baseball players tested at Athletes’ Performance typically register modest V02 scores in the mid-40s since theirs is a sport of anaerobic activity. Professional cyclists, on the other hand, record V02 scores in the 70s, meaning they use 70-plus milliliters of oxygen per kilogram of body weight per minute.

As an age-group triathlete, my numbers figured to land somewhere in the middle. I began following the Core Performance program late in 2002 when I began writing the original Core Performance book with Mark Verstegen. A non-swimmer at the time, I took up triathlon late in 2006, following the Core Performance Endurance program.

When I was first tested at Athletes’ Performance in December of 2006, having just begun triathlon training, my V02 max was a modest 43.7. That would have been fine if I was playing second base for the Boston Red Sox, but it was pretty weak for a triathlete. Two years and 11 sprint triathlons later, in December of ’08, I checked in at 53.8.

About the Test

The VO2 test takes between 8 and 12 minutes and it’s not an easy one. An air mask is placed over your head and you begin jogging on a treadmill set at an incline. My protocol was 8 mph and Robbins very quickly (or at least it seemed to me) brought me up to a maximum heart rate of 192. He could have gone with a slower protocol, but he did not want my legs to tire before I hit my V02 max.

During a test in March ‘09 at Athletes’ Performance, my V02 max was 52.2. That seemed like a setback from December, especially given my heavy training of the last three months, but Robbins actually saw it as an improvement. That’s because my ventilatory threshold (VT), the point before where my body begins to produce more carbon dioxide than oxygen, was 47.1. The ratio of my VT to V02 max was 90 percent. Three months earlier, it was 84 percent.

“The percentage indicates how soon you turn anaerobic and then peak out,” Robbins says. “For an endurance athlete, we want it at least around 90. That means you can sustain it around your anaerobic threshold for a longer period of time.”

Robbins says the ratio is at least as important as the V02 max number, especially once the V02 reaches 50. Just as it becomes incrementally more difficult to reduce body fat once you reach 10 percent, it’s increasingly challenging to boost your V02 once you clear 50.

It’s also noteworthy that my heart rate after two minutes was down to 109, less than the 113 of my previous test. For endurance athletes, that’s a key measurement since it dictates how quickly you can recover for the next interval.

Improve Your Numbers

To improve your V02—as well as triathlon performance—the key is to engage in progressively harder interval training. Robbins again provided me with a protocol of interval days, recovery sessions, and medium intensity days.

The sessions include one-minute intervals that raise my heart rate to as high as 195. For a 39-year-old, that seems to fly in the face of the traditional 220-your age training prescription, but as an endurance athlete, my heart rate can go higher.

The idea, Robbins says, is to get me training in the heart rate zones near where I was at the end of the V02 max test. Once I’m able to do that consistently, my V02 max inevitably will rise and my protocol will need to be tweaked again.

“As an endurance athlete, you want to be able to sustain that longer and longer,” Robbins said. “That, in the end, is what’s going to make you a much better triathlete.”

About The Author

Pete Williams – Pete Williams is a contributing writer for CorePerformance.com and the co-author of the Core Performance book series.

Read Full Bio

Tags: Energy System Development, Triathlon, Cardio, Cycling, Running, Conditioning