Want To Improve Your VO2 Max? This Sports Scientist’s Protocol Delivers Real Results

I've been thinking a lot about VO2 max lately. Not in the abstract "longevity biomarker" way, but in the very practical "I want to actually improve mine without dedicating my life to it" way. So when sports scientist Fraser Thurlow came on the mindbodygreen podcast, I had a lot of questions for him.

The most common error Thurlow encounters in his personal training clients is seeing them copy elite athletes.

Elite endurance athletes accumulate enormous training volumes over years and years. They might do 20 reps of 400-meter efforts in a single session. Their programs are built on a foundation of training history that most of us don't have. When everyday people try to replicate that volume and intensity, they easily burn out, plateau, or get hurt.

Thurlow's advice is to draw inspiration from what elite athletes do, then scale it way down. "Take ideas from what they do, but then use it in your own individual context, and most of the time that's reducing the intensity and the volume and the duration of exercise," he told me. Instead of 20 reps of 400s, do eight to ten. Instead of eight rounds of the Norwegian 4x4 protocol, do four to five. The principle is the same. It's the dose that's different.

The other mistake is getting stuck in one style of training. A lot of people pick a lane and stay there, whether it's only doing zone training, HIIT, or threshold work. But Thurlow says that's leaving a lot of gains on the table.

A landmark 2007 study by Norwegian physiologist Jan Helgerud1 compared different training methods head-to-head: long high-intensity intervals (the 4x4 protocol), short high-intensity intervals (15 seconds on, 15 seconds off), and lower-intensity continuous work. When performed twice a week over several weeks, the long intervals produced the best VO2 max improvements. Short intervals came in a close second. Both were more time-efficient than steady-state work.

But Thurlow doesn't recommend picking the winner from that study and doing it forever. It's using all of them together. "A range of different intensities and durations will lead to a range of adaptations that all work together to ultimately improve VO2 max," he says.

Sprint interval training, for example, works through a completely different mechanism than long intervals. It creates a rapid oxygen demand and high metabolic stress that drives long-term changes in how your body produces and uses energy. So you don't have to choose one method, you have to vary them.

Thurlow also shared something surprising about sprint interval training specifically. According to a 2017 meta-analysis analyzing 34 training studies2 found that just 20 minutes of sprint interval training per week can improve VO2 max by around 7.8% in everyday people. Two reps of 20-second maximal sprints, performed three times a week for six weeks, improved VO2 max by 10% across two separate studies.

The 4x4 Norwegian protocol is the the gold standard for VO2 max improvement. You work four minutes of effort above 90% of your max heart rate, followed by three minutes of active rest, and reapeat it four times. It's hard, but it's effective.

For this type of training, Thurlow recommends doing two to six sprints of 20 to 30 seconds each, with three to four minutes of rest between efforts. "The most important part is that it's maximal—we're not going at 80%, we're truly sprinting maximal," Thurlow says.

This three-day-a-week protocol is an ideal schedule for leveling up your VO2 max, but not everyone has time to dedicate three days a week to cardio. Thurlow says you can still get meaningful VO2 max benefits by tacking 10 to 30 minutes of high-intensity work onto the end of a resistance training session, and it won't interfere with your strength or muscle gains. If anything, it complements them, since sprint-style work also builds power and anaerobic capacity.

I do three days of resistance training a week and three days of rowing. What Thurlow confirmed is that the variability I've built into my rowing sessions, mixing hard efforts, sprints, and easier work, is actually an effective approach. As long as you're training across different intensities and durations, you're getting the stimulus your body needs.

The minimum effective dose for meaningfully improving your VO2 max is more accessible than you might think. You don't need to train like a professional endurance athlete. You need three sessions a week (or just two, if that's what you have time for) that hit different points on the intensity spectrum.