VO2 Max Training: How to Raise Your Aerobic Engine

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Third set of a tight tennis match. The cyclist dropping off the back of the group on the second climb. The midfielder who can still press in the 85th minute while everyone else is walking. A lot of that comes down to one number: VO2 max, the size of your aerobic engine. VO2 max training is the kind of hard interval work that pushes that engine to grow. Here’s what VO2 max is, the workout with the best-known research behind it, how to fit it into your week, and the gear that helps you do it right.

What VO2 max is

VO2 max (maximal oxygen uptake) is the greatest amount of oxygen your body can use during intense exercise, measured in milliliters of oxygen per kilogram of body weight per minute. A higher number means your heart, lungs and muscles can deliver and use more oxygen, which supports faster paces and harder efforts in almost every endurance and team sport.

It’s measured precisely in a lab on a treadmill or bike with a mask. Many sports watches and trackers now show an estimate too. Treat the watch number as a trend line: useful to see whether you’re moving in the right direction, less useful as an exact value.

The 4×4 workout: VO2 max training with the most research

The best-known VO2 max workout comes from Norway. Jan Helgerud, Jan Hoff and colleagues at the Norwegian University of Science and Technology (NTNU) studied what’s now called the 4×4: four 4-minute hard efforts at about 85–95% of maximum heart rate, each followed by 3 minutes of active recovery at about 70% of max.

In their 2007 study in Medicine & Science in Sports & Exercise, moderately trained men did 4×4 running intervals at 90–95% of max heart rate three times a week for 8 weeks. The intervals raised VO2 max significantly more than doing the same total work at lactate threshold or at 70% of max heart rate. The researchers concluded that high-intensity aerobic intervals were “significantly more effective” for improving VO2 max. Later studies, summarized in a 2020 paper on the 4×4 protocol, found similar results in other groups, including a 10% rise in VO2 max after 6 weeks in one group of adults with obesity.

How to do a 4×4 session

1. Warm up for about 10 minutes, easy at first, then a little faster.
2. Run (or ride, row, skate) hard for 4 minutes. Your heart rate should climb into the 85–95% of max zone by the second or third minute. It should feel very hard, but you should be able to hold the same effort for the full 4 minutes.
3. Recover actively for 3 minutes: an easy jog or spin, not standing still.
4. Repeat for four hard efforts in total.
5. Cool down for 5 to 10 minutes easy.

The whole session takes about 40 minutes. Hills work well if your flat route is busy: run up for 4 minutes, jog down for 3. Cyclists can do it on the trainer; swimmers and rowers can adapt it by time.

Other ways coaches train VO2 max

The 4×4 isn’t the only option. Coaches also use hill repeats of 2 to 5 minutes, track intervals such as 5 x 1,000 meters with short jog recoveries, and shorter on-off sets like 30 seconds hard and 30 seconds easy for 10 to 20 minutes. What they share is time spent close to your maximum heart rate, with recoveries short enough that the next rep starts before you’re fully rested. For team-sport athletes, small-sided games and shuttle runs can do a similar job in a more sport-specific way; that’s why preseason soccer, hockey and basketball sessions often feel like VO2 max work.

Pick the version you enjoy and can repeat. The best interval plan is the one you actually do for 6 to 8 weeks, not the one you abandon after two sessions.

How often to do VO2 max workouts

The 2007 study used three sessions a week for 8 weeks, but those subjects weren’t also doing long runs and team practices. For most athletes, one hard interval session a week, sometimes two, is plenty alongside the rest of training. The rest of the week should be mostly easy. If you’re new to running or training for your first marathon, build an easy base for a few months before adding intervals; our first marathon guide explains why.

Signs you’re overdoing it: you can’t hit the heart-rate zone on the third or fourth rep, your easy runs feel hard, you sleep badly or feel flat for days. Back off for a week. Recovery between hard sessions is part of the training, and our recovery for runners guide covers the basics.

Finding your max heart rate

Age-based formulas only give a rough guess for any one person. A better way is to look at the highest heart rate you’ve seen in a hard race or an all-out hill effort on a chest strap. If you have any heart condition, take medication that affects heart rate, or haven’t trained hard before, talk to your doctor before maximal efforts. The 4×4 has been studied in people with heart disease, but within clinical programs, not on their own.

Gear that helps

Prices change often. The prices below are what we saw at the maker or a major retailer in October 2026; check the current price before you buy.

• Garmin HRM 600: many athletes prefer a chest strap to a wrist sensor for hard intervals. Garmin’s $169.99 strap sends heart rate and HRV to compatible devices, records on its own during team sports when you can’t wear a watch, is machine washable and recharges for about 2 months of use.
• Garmin Forerunner 570: a GPS running watch (about $549.99 at launch) with Training Readiness, HRV Status and Garmin Coach plans for running, cycling and strength. See best Garmin for runners for other models.
• Amazfit Helio Strap: a screenless band (about $99.99) worn on the wrist or upper arm that shows a VO2 max estimate, HRV and recovery data in the app, with no subscription.

Want more speed tools for team sports? See best speed training equipment, or browse the running section. Soccer players can find season-specific advice on our soccer page.

VO2 max training questions

What is the best workout to increase VO2 max?

The 4×4 interval (four 4-minute efforts at about 85–95% of max heart rate with 3-minute active recoveries) has the most research behind it. In the 2007 Helgerud study it beat moderate continuous training and threshold training for raising VO2 max.

How long does it take to improve VO2 max?

In the studies above, measurable gains showed up after 6 to 8 weeks of regular interval training. How much you gain depends on where you start; less-trained people usually improve more.

How many times a week should I do VO2 max intervals?

One session a week is a good start for most athletes, two at most during focused blocks, with easy days in between. The lab studies used three, but without other hard training on top.

Is my watch’s VO2 max accurate?

It’s an estimate, not a lab test. Use it to watch the trend over weeks, and wear a chest strap if you want more reliable heart-rate data during hard efforts.

Can I do VO2 max training on a bike or rower?

Yes. The 4×4 is about time and heart rate, so it works on a bike, rower, ski erg or in the pool. Cross-training intervals are also gentler on your legs if you’re coming back from a running niggle.