VO2MAX
How to improve your VO2max
Train most of your week easy and add hard interval sessions, such as 4 efforts of 4 minutes with 3 minutes of easy recovery. One a week is our starting advice. In 19 trained cyclists, one week packed with interval sessions followed by one a week raised VO2max, where two a week did not, and a pooled analysis of 348 endurance athletes found no single mix of easy and hard training beat the others. Complete starts from your long-term goals, such as improve cardio, and it takes your VO2max from a lab test, a field test such as the Cooper test, or your watch.
What VO2max is and why people chase it
VO2max is the most oxygen your body can use during hard effort. It is one of three factors that set endurance performance, next to your lactate threshold, the hardest steady pace you can hold, and your efficiency, how much oxygen a given pace costs (Joyner and Coyle, 2008).
The link shows up in Hyrox too. In a study of 11 recreational athletes in a simulated race, higher VO2max and more endurance training went with faster times. The runs followed that link. The stations did not (Brandt and colleagues, 2025).
What the research says about raising it
Hard intervals are the usual tool. In 19 trained cyclists, one week of packed interval sessions followed by easier weeks raised VO2max, peak power and power at a low lactate level. The same work spread over two sessions a week did not (Rønnestad and colleagues, 2014). Our research set has no running-only trial of this kind, so cyclists are the evidence for this point. Treat it as a guide for other sports.
No single mix of easy and hard training won. A pooled analysis of 13 studies and 348 endurance athletes found no overall difference between a polarized mix and the other mixes, for VO2max or for time trials. Polarized means most of the work is easy, some is hard and little sits in between. Competitive athletes may gain more VO2max from a polarized mix, and recreational athletes from a pyramid mix, which has the most time easy, less at moderate effort and the least time hard (Rosenblat and colleagues, 2025).
Jumps and lifts aim at a different target. A meta-analysis of 21 studies found that jump training improved running economy and 2 to 5 kilometer time trials with no change in VO2max (Ramirez-Campillo and colleagues, 2021). You can run faster by raising VO2max or by spending less energy at the same pace, and a strong week works on both.
- Rønnestad et al., Scand J Med Sci Sports, 2014: block periodization of high-intensity intervals in cyclists checked 19 Oct 2026
- Rosenblat et al., Sports Medicine, 2025: training intensity distribution, VO2max and time trials checked 19 Oct 2026
- Ramirez-Campillo et al., Journal of Sports Sciences, 2021: jump training in endurance runners checked 19 Oct 2026
A VO2max week
Keep one hard day and surround it with easy work. Easy means a pace where you could hold a conversation, often called Zone 2. This is general training advice, so move the days to fit your life. Your heart rate zones show where your easy and hard efforts sit, and Complete sets them from your own data.
| Day | Session | Why |
|---|---|---|
| Monday | Easy cardio, 30 to 45 minutes | A run, a ride or a row at conversation pace builds your aerobic base. |
| Tuesday | VO2max session: the 4 x 4 below | The one hard day. Four efforts of 4 minutes, with 3 minutes of easy recovery between them. |
| Wednesday | Strength or rest | Lifting and jumping work on your economy, the energy a pace costs. |
| Thursday | Easy cardio, 30 to 45 minutes | More base work with little fatigue. |
| Friday | Rest or a walk | Your body adapts to the hard day while you rest. |
| Saturday | Long easy session, 60 minutes or more | Time at an easy effort adds up to your base. |
| Sunday | Rest or a walk | Arrive at Tuesday fresh. |
How hard is hard enough
Most people hold back on the hard day and push too much on the easy days. This is general training advice that none of the studies above tested. On an interval day, the first effort should feel controlled and the last one should leave you short of breath. If you finish the fourth effort with plenty left, go a little harder next time.
On the easy days, hold a pace where you could talk in full sentences. Complete sets your zones from your own heart data: it analyzes the workouts in your Apple Health history, and a lab test or the in-app test also sets them. With no usable history it starts from an age formula and replaces it once your own data arrives. Our guide to heart rate zones from your own data shows how, so you can match a number to that pace.
A VO2max session from Complete’s workout library
This is the Erg Engine 4 x 4, a Norwegian 4 x 4 on an erg, an indoor machine such as a rower, a SkiErg or a bike erg. It builds your engine without the pounding of running. It takes about 40 minutes. Effort 9 out of 10 means hard, with heavy breathing by the end of each effort.
Pace the first effort so the last one still holds the same split. A split is your time for each 500 meters on a rower, or the matching pace on the machine you use.
| Block | What you do |
|---|---|
| Warm-up | Row Erg: 5 minutes at effort 4 out of 10, on the machine you will work on. Ramp from easy to moderate until you break a light sweat and your lungs open. |
| Main: 4 rounds, 3 minutes of rest between rounds | Row Erg: 4 minutes at effort 9 out of 10. |
| Cool-down | Row Erg: 5 minutes at effort 2 out of 10, an easy flush on the same machine. |
Scaling the 4 x 4
If you are new to intervals, keep the effort hard but repeatable, about 8 out of 10, and take the full 3 minutes of rest. If you have trained hard before, hold a tight split across all four efforts and cut the rest to 2 minutes 30 seconds. Choose the erg that suits you. The library also has the same session as a run, the Norwegian 4 x 4.
How Complete handles VO2max
Complete starts from your long-term goals: build muscle, lose fat, improve cardio, get stronger, general health or become an athlete. Improve cardio fits this page. The goals steer what Complete recommends every day, and you do not need a plan to use it.
Complete takes your VO2max from a lab test you import, a field test, a number you type in, a fresh reading from your watch or your Apple Health history. The field tests are the Cooper 12-minute test, where you run as far as you can in 12 minutes, and a Complete ramp test. VO2max is an input to Complete Age, alongside resting heart rate, HRV and functional fitness. Training consistency is not counted yet. The sessions on this page train your fitness. To see where you stand, take a test again after a few weeks of training.
Every workout that reaches Apple Health counts toward your score and the recommendation for each day, from any watch. If your watch records HRV and resting heart rate, Complete scores your recovery against your own baseline after about a week of data. If your recovery is red, today’s session turns into rest or an easy session.
Start with your goal. Complete is an iPhone app, free to download, and logging and sharing your workouts on it stay free.
Frequently asked questions
What is the fastest way to improve VO2max?
No study in our research set ranks the methods, so we cannot name a fastest one. Hard intervals are the usual tool. In 19 trained cyclists, a week of packed interval sessions followed by easier weeks raised VO2max, and the same work spread over two sessions a week did not.
How often should I do VO2max intervals?
One hard interval session a week is a sound start, with easy work around it. The research we use found no single best mix of easy and hard training, so build a week you can repeat.
Can I improve VO2max without running?
Yes. Intervals on a rower, a SkiErg or a bike erg build the same engine with less pounding on your legs, and the cyclist trial above used a bike. The 4 x 4 in Complete’s library runs on the erg of your choice.
Does lifting or jumping raise VO2max?
Jump training improved running economy and 2 to 5 kilometer time trials with no change in VO2max in a meta-analysis of runners. Strength work changes how much energy a pace costs, so it sits next to intervals in your week and does not replace them.
Does Complete track my VO2max?
Complete takes VO2max from a lab test you import, a field test such as the Cooper 12-minute test or a Complete ramp test, a number you type in, or your watch through Apple Health. It uses VO2max in Complete Age.