Brains
As a cross-country and track runner, I remember the first time I had my VO2 max tested. It was early season and my legs were still sore from the week’s mileage. The number flashed on the screen: “65 ml/kg/min.” I stared at it longer than I probably needed to. 65. Okay—that’s solid. And for a distance runner, it is solid. More than solid, honestly. Most people never see a number anywhere near that. At the time, I felt proud. Validated, even. It felt like proof that the early mornings and tempo runs meant something measurable.
Then I started watching cross-country skiing. Following the FIS Cross-Country World Cup and the Winter Olympics, I was shocked when hearing commentators mention values in the 80s. Sometimes the 90s. It sounded routine, the way someone might mention a batting average. Suddenly, 65 didn’t feel like much.
VO2 max (short for maximal oxygen intake) is the maximum amount of oxygen your body can use during intense exercise. When you’re working hard, your muscles run on oxygen. The more your body can pull in, pump through, and actually use, the more energy you can generate aerobically. It’s the whole system at once: lungs, heart, blood, muscles. When it tops out, that’s your ceiling.
Cross-country skiing hits that ceiling constantly. Even sprints last several minutes at nearly an all-out effort. Distance events range from 10km to 50km over relentless terrain, often at altitude, in the cold. Skiers surge up climbs, get a few seconds of recovery on the descent, and surge again. Elite Nordic skiers consistently rank among the highest VO2 max athletes ever recorded. For reference: average adults test somewhere between 30 and 45 ml/kg/min. Recreational endurance athletes sit around 45 to 60. Competitive distance runners, 60 to 75. Elite male Nordic skiers? Regularly 80 to 95 and above. Elite women, 70 to 85 and above.
That gap exists for a reason. Nordic skiing demands sustained, hard effort from the upper and lower body simultaneously—something almost no other endurance sport does. Double poling, skating, grinding up steep climbs with everything firing at once. Over years of training, cross-country skiing forces serious adaptation. The heart pumps more blood per beat. Capillaries expand inside working muscles. Mitochondria multiply. Athletes like Klæbo and Johaug compete in a sport that essentially selects for people with extraordinary aerobic capacity and then pushes that capacity as far as it’ll go.
But VO2 max doesn’t decide races on its own. If it did, whoever tested highest would win every time, and that’s not what happens. It sets the ceiling. What matters is how close to that ceiling an athlete can actually operate, for how long, without falling apart. Two skiers with identical VO2 max values can perform very differently based on lactate threshold, efficiency, and tactics. The skier who glides cleaner wastes less energy per stride and can move faster at the same oxygen cost. Over 50 km, those small differences compound.
You can train your VO2 max. Intervals, long aerobic sessions, strength training, altitude exposure—all of it helps. The biggest improvements usually come early, when the body is most responsive. After that, progress slows. There’s a genetic component, too. At some point, most athletes approach their personal ceiling, no matter how disciplined they are.
Some athletes chase the margins aggressively. Norwegian biathlete Sivert Guttorm Bakken died while training for the 2026 Winter Olympics, reportedly wearing a high-altitude simulation mask. Authorities didn’t establish a definitive link between the device and his death. But it was a reminder of how far some athletes will push to find even a small physiological edge.
I still think 65 is a solid number. But spending time watching Nordic skiing recalibrated something for me. Those values in the 90s aren’t just impressive data points—they’re the result of genetics, years of hard training, and a sport that is almost uniquely brutal in what it asks of the human body.
For most athletes, progress is slower and steadier. The biggest gains usually come early, but as training age increases, improvements shrink and are harder to earn. Looking back, I still think 65 is a strong number for a runner. But compared to elite Nordic skiers, it’s humbling. And that makes sense. For them, VO2 max is built on genetics, staggering training volume, and years of work in harsh conditions. So the next time you hear someone casually mention a VO2 max in the 90s, perhaps pause to appreciate just how physically and aerobically demanding cross-country skiing really is.
