How to improve VO2 max: what raised it in the trials, without running, and a week to run

VO2 max, short for maximal oxygen uptake, is the highest rate your body can take up oxygen during exercise. A 2000 review explains that in an exercising person it is limited by how well the cardiorespiratory system delivers oxygen to the working muscles, and that it sets an upper limit on endurance performance: an athlete can't work above 100% of it for long.¹ It is usually written in millilitres of oxygen per kilogram of body weight per minute, mL/kg/min.²

This page is the training question: what raised VO2 max in trials, how long it took, how to do it without running, and a week built around it. It's about the number as a fitness measure, not a promise about anything else. The steady end is on zone 2 cardio, the comparison is on HIIT vs steady-state cardio, and a session to run is on the HIIT workout.

What raised it in the trials

• Both steady training and intervals. A 2015 meta-analysis pooled 28 controlled trials of 723 healthy adults aged 18 to 45, average age 25, who started at an average of 40.8 mL/kg/min. Against no exercise, steady endurance training raised VO2 max by about 4.9 mL/kg/min and interval training by about 5.5. Head to head, intervals came out about 1.2 ahead, which the authors rated a possibly small benefit. Against no exercise, they also found a likely moderate extra increase from intervals in people who started with lower fitness.²
• Intervals generally more, for a given volume. A 2017 review concluded that VO2 max is generally increased more by high-intensity intervals than by steady training for a given training volume, while sprint intervals and steady training improve it similarly despite the difference in volume.³
• Longer intervals for the biggest gains. A 2019 meta-analysis of 53 randomized trials in adults found that short intervals of 30 seconds or less, low-volume sessions (5 minutes or less, in the review's classification) and programs of 4 weeks or less all improved VO2 max compared with controls. Only intervals of 2 minutes or more, high-volume sessions (15 minutes or more) and programs of 4 to 12 weeks or longer beat steady training. The authors recommend longer intervals, volumes and programs to maximize the gain, and the shorter ones as a time-efficient option.⁴
• The 4-by-4. In 40 healthy, nonsmoking, moderately trained men, four running programs matched for total work, three days a week for 8 weeks, were compared. Intervals of 4 minutes at 90% to 95% of maximum heart rate with 3 minutes of active rest at 70% raised VO2 max 7.2%, and 15-second intervals with 15 seconds of active rest raised it 5.5%. Both beat the long slow distance group (70% of maximum heart rate) and the lactate-threshold group (85%).⁵
• Very short sprints. In 9 sedentary men, three 20-second all-out cycle sprints with 2 minutes of easy cycling between, in a 10-minute session three times a week for 12 weeks, raised peak oxygen uptake 19%. So did 45 minutes of steady cycling in 10 men.⁶
• Across 37 interval studies. A 2013 meta-analysis of interval training, alone or combined with steady training, in healthy sedentary or recreationally active people under 45, 334 in all and 120 of them women, found VO2 max rose by an average of 0.51 litres a minute. A subset of 9 studies with longer intervals showed larger changes, about 0.8 to 0.9 litres a minute, with a marked response in all the subjects in those studies.⁷

Read together: in these trials, regular cardio of either kind moved VO2 max in healthy adults. Intervals did it with less time in some of them, longer intervals did it most, and the programs ran for weeks.

Without running

Most of the trials above used cycling or running, but the effect wasn't tied to a machine.

• A bike. The sprint trial above was all cycling.⁶
• A jump rope. In 59 healthy adults, average age about 22, 8 weeks of interval skipping (9 bouts of 2 minutes at 80% of maximum heart rate, three times a week) or steady skipping (30 minutes at 70%, five times a week) raised VO2 max from about 44 to 48 and 42 to 47 mL/kg/min, and both ended above the group that didn't exercise. More on the jump rope workout.⁸
• Bodyweight moves at home. In 7 recreationally active women, 8 efforts of 20 seconds with 10 seconds of rest, one exercise such as burpees or mountain climbers, 4 days a week for 4 weeks, raised peak oxygen uptake about 8%.⁹ Burpees and mountain climbers have their own pages.

A week to run

Three interval sessions, from easiest to hardest. They're built on the shapes in the trials, and they're practical starting points, not their protocols. "Hard" means a few words at most; the World Health Organization describes vigorous effort as usually a 7 or 8 on a 0-to-10 scale.¹⁰ The 4-by-4 trial set its effort by heart rate; effort is a workable stand-in.

Then place them. This is a practical week beside three lifting days:

Start with one interval session a week for two weeks, then two, the same ramp as the HIIT workout. Keep the hard day away from a heavy leg day; cardio and lifting covers how far apart. Run it for four weeks or more before judging it; the single trials above ran 4 to 12 weeks.

How to tell it's working

A lab test gives the number. Without one, repeat the same session every four weeks, on the same route or machine with the same warm-up, and compare how far or fast you get at the same effort, or how your heart rate sits at the same pace. That's a practical check, not a VO2 max measurement.

Common questions

How long does it take to improve VO2 max?

The single trials above ran 4 to 12 weeks. In the 2019 meta-analysis, interval programs of 4 weeks or less already beat doing nothing, and programs of 4 to 12 weeks or longer did better than steady training.⁴ The 4-by-4 and rope trials were 8 weeks, and the sprint trial 12.^5,8,6

Can I improve VO2 max without running?

Yes. A bike, a jump rope and bodyweight efforts each raised it in the trials above.^6,8,9

Does everyone improve by the same amount?

No. In the 28-trial analysis, against no exercise, intervals gave a likely moderate extra increase to people who started with lower fitness.² The 2013 authors noted that endurance training studies frequently show modest changes and very limited responses in some people, while their subset of 9 studies and 72 subjects with longer intervals showed evidence of a marked response in all subjects.⁷

Intervals or steady cardio?

Both raised it. In the 28-trial analysis intervals came out a possibly small 1.2 mL/kg/min ahead,² and the 2017 review found VO2 max generally increased more by intervals for a given volume.³ HIIT vs steady-state cardio compares them. A week with one or two hard sessions and one or two easy ones is a practical mix of the two.

Should I check with a doctor first?

If you have a heart or lung condition, or a medical reason to limit hard exercise, a doctor should set the limits before you start intervals; this page is general guidance for healthy adults.

If you'd rather have the week planned

Hard sessions work when they land on the right days, and that's a scheduling problem as much as a training one. Coaching is the version where your workouts live in Trainerize, built around the days you actually have, and a weekly call looks at the week you just had and rebuilds the next one. How coaching works explains the rest, and apply is the first step. Otherwise: run the starter session once this week, then once more next week.