The average male has a VO2 max consumption of 35-40 millilitres per minute per kilogram of body weight. Andrew Musgrave's is double that.
Indeed, of the top 10 VO2 max measurements in history, cross-country skiers are responsible for half of them - perhaps not surprising when you think about what it takes to ski 50km, partly uphill, at speed.
The calculation itself is the maximum amount of oxygen a person can use during intense exercise, an overall measure of aerobic fitness and cardiovascular endurance. In slightly easier to understand terms: the higher your number, the more energy you can produce.
For Britain's top cross-country skier, Musgrave, measuring VO2 max is a key part to his season, even if he doesn't want it to be.
And for the average Joe who is watching on as the 34-year-old aims to clinch a spot at his fifth Olympic Games, it's a tell tale sign of just how superhuman cross-country skiers really are.
"We test three or four times during the training season and it's a super good tool for monitoring a tracking progress," he said. "But I hate it just as much every time.
"For V02 max, I am somewhere between 80 and 85 depending on when in the season we are.
"To compete in cross-country skiing you've got to have hit the high max generally and there are a couple of outliers who are in the 90s.
"For other sports, being in the 80s is very high and there are very few people who have that, but in cross-country skiing it's pretty common."
With his lungs taking in more oxygen than most, Musgrave clinched his fifth career World Cup podium with bronze in stage three of the Tour de Ski World Cup in December.
The 34-year-old finished the 20km interval start freestyle in 44:33.7s, gracing the podium for the first time in over a year.
A fifth career World Cup podium = the perfect way to end a year 😍🖐️
— Team GB (@TeamGB) December 31, 2024
Andrew Musgrave has taken third place in the 20km Interval Start F stage of the Tour de Ski World Cup 🥉@GBSnowsport pic.twitter.com/zMf79PDTBd
After a difficult start to the season which saw him trailing at the bottom of the standings, it was a brilliant return to form.
"I knew when I looked at the Tour programme before the races that that stage would suit me well as it was a longer stage with a long climb but not too steep," he said.
"I felt going into the Tour that I was on really good form, so going into the race I felt really good.
"Things came together and I was back on the podium which was very nice as it's been a while."
A podium finish and several top 20 performances this season are setting Musgrave up perfectly for the pinnacle of the 2025 cross-country calendar: the World Championships in Trondheim, Norway.
Cross-country skiing isn't just a sport in Norway, it's a way of life, and thousands are set to flock to the global event.
For Musgrave, who now lives in Trondheim, it is basically a home competition. He skis the competition tracks every day as part of his training - an advantage he hopes can catapult him onto the podium once more.
"For cross-country skiers, this year is massive," he said.
"Having a worlds in Norway is huge. Cross-country is one of the biggest sports in the country and there will be hundreds of thousands of people watching so it really will be a highlight of the decade.
"I know the tracks like the back of my hand which definitely helps. We had the test event for worlds as a World Cup last season and I was on the podium then so it really gave me a confidence boost."
The World Championships may be at the forefront of Musgrave's mind right now, but the quickly approaching time scale of the Milano Cortina 2026 Winter Olympics cannot be ignored.
Musgrave has the opportunity to reach his fifth Olympics next season, having first competed as a sprightly teenager at Vancouver 2010.
His best-ever finish came with seventh place in the men's 30km skiathlon at PyeongChang 2018 and now on the more experienced side of his career, Musgrave is chasing the elusive Olympic medal that has evaded him for so long.
"As a British athlete, the Olympics is by far the biggest thing we ever do," he said.
"The last couple of Games have been in places where cross-country isn't the biggest of sports so going to Italy is going to be an awesome event.
"I'm confident I'm going to be there and I feel like I'm going there as a medal candidate.
"In my first couple, I was young and still progressing as an athlete, while now I might be getting to the tail end of my career but I feel I'm better than I've ever been."
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