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How to Improve VO2 Max: The Training Mix, the Timeline, and How to Measure It

How to improve VO2 max with an easy aerobic base, one or two interval sessions a week, and strength work, how long it takes, and how to tell from a retest whether it worked.

Published

November 27, 2025

Last updated

October 28, 2026

Read time

9 min read

Medically reviewed by

Rhonda Collins, FNP-C

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To improve VO2 max, build an easy aerobic base on most days of the week, add one or two harder interval sessions, keep two days of strength work, and stay consistent for 8 to 12 weeks. That mix is what training studies reward. Then measure it: a test before and after the training block tells you whether your VO2 max really changed, and a change of more than about 5% is real progress.

VO2 max is the most oxygen your body can take in and use during an all-out effort, usually reported in milliliters per kilogram of body weight per minute. In most people it is limited by how much oxygen-rich blood the heart can deliver to working muscle, which is why training that raises the heart’s output per beat raises VO2 max ^[1]. Low cardiorespiratory fitness has been associated with a risk of death comparable to smoking or diabetes in a study of about 122,000 adults who had treadmill tests ^[2]. That is an association, not proof of cause, but it is why the number is worth improving.

The Training Mix That Improves VO2 Max

Three kinds of training work together to improve VO2 max: easy aerobic volume, short blocks of hard intervals, and strength work. Each does a different job, and the combination matters more than any single workout.

An easy aerobic base, including zone 2

Most of your weekly aerobic time can be easy: a pace where you can still hold a conversation, such as brisk walking, easy cycling, jogging, rowing or swimming. This easy work, often called zone 2, is the base that lets you recover from and repeat harder sessions. US guidelines recommend 150 to 300 minutes a week of moderate aerobic activity for adults, which is a sensible range for this base ^[3].

One or two interval sessions a week

Hard intervals are where most of the change in VO2 max comes from once you have a base. The best known format is the 4x4 protocol. In the original trial, moderately trained young men ran four 4-minute intervals at 90 to 95% of maximum heart rate, with 3 minutes of easy jogging between them, three times a week for 8 weeks. Their VO2 max rose by 7.2%, more than in groups that did the same total work at a steady easy or threshold pace ^[4].

Across 28 controlled trials in healthy adults aged 18 to 45, both endurance training and high-intensity interval training produced large VO2 max gains compared with no exercise, with a small extra benefit for intervals ^[5]. In people with lifestyle-related conditions such as obesity, hypertension and metabolic syndrome, interval training raised peak VO2 by about 9% more than moderate continuous training ^[6]. One or two interval days a week, on top of easy aerobic work, is a practical way to apply this.

Strength training two days a week

Strength work is not the main driver of VO2 max, but it belongs in the plan. US guidelines recommend muscle-strengthening activity on 2 or more days a week alongside aerobic activity ^[3], and stronger legs and hips make running, cycling and climbing stairs easier to sustain. Compound movements such as squats or leg presses, hinges, rows, presses and loaded carries cover the main muscle groups.

How Long It Takes to Improve VO2 Max

Expect measurable change in 8 to 12 weeks of consistent training. In a meta-analysis of interval training studies lasting 6 to 13 weeks in healthy, previously sedentary or recreationally active adults under 45, VO2 max rose by about 0.5 liters per minute on average, and programs with longer intervals produced larger gains ^[7]. In the 4x4 trial, an 8-week block raised VO2 max by 7.2% ^[4].

Whether you think of it as improving or increasing VO2 max, the size of the change depends on where you start and how much you train. Less fit people tend to gain more ^[5]. Training intensity and training volume trade off: higher-intensity programs reached similar gains with less total training time ^[8]. Longer programs keep adding: in older adults, gains were larger in programs lasting more than 20 weeks ^[9].

How to Tell Whether Your VO2 Max Really Improved

Measure before and after the training block, on the same type of test. A fitness watch estimates VO2 max from heart rate and pace. A lab test measures it from the air you breathe during a progressive exercise test, and it also finds your own heart rate training zones, so you stop guessing from age formulas.

Use this rule for reading the result:

• Test before you start and again after 8 to 12 weeks of training.
• A change of more than about 5% between tests is real progress.
• A change of less than about 5% is within normal day-to-day variation, so treat it as no change yet.
• Retest on the same type of machine. Treadmill and bike results differ.
• Give it your full effort both times. Stopping early gives a lower number than your true maximum.

To get a baseline, the VO2 Max Test is a guided exercise test at a partner testing center. Depending on your health answers, you may need clearance from your own doctor before your appointment is confirmed. To compare it with university labs, gyms and other services, see what a VO2 max test costs near you.

Why Is My VO2 Max Low Even Though I Exercise?

A VO2 max that stays low despite regular exercise usually comes down to the type or amount of training, your individual response, or how the number was measured.

• Most of your training is easy. In the 4x4 trial, moderately trained men who did the same work at an easy or threshold pace improved less than those who did hard intervals ^[4]. Adding one or two interval sessions is the usual fix.
• The weekly dose is too low. In a 6-week trial, 69% of people training one hour a week showed no meaningful fitness gain, while none of those training four or five hours a week were non-responders. When the non-responders then added two more sessions a week for another 6 weeks, every one of them improved ^[10].
• You respond less than average. In the HERITAGE Family Study, 481 sedentary adults did the same 20-week program. The average gain was about 0.4 liters per minute, but some people gained little or nothing and others gained more than 1 liter per minute. The response ran in families, with an estimated heritability of 47% ^[11].
• The number is an estimate. A watch estimates VO2 max rather than measuring it, so a low or stuck reading may not reflect your true value. A lab test settles it.
• A medication limits your heart rate. VO2 max depends on how much blood the heart delivers, and drugs that blunt heart rate, such as beta-blockers, change it accordingly ^[1].

Does Losing Weight Improve VO2 Max?

Losing weight raises VO2 max as it is usually reported, but not your heart’s oxygen delivery by itself. Most results are relative VO2 max, in milliliters per kilogram of body weight per minute. Absolute VO2 max, in liters per minute, is the same measure before dividing by body weight.

The arithmetic shows why. Someone with an absolute VO2 max of 3.0 liters per minute who weighs 90 kg has a relative VO2 max of about 33. If they lose 9 kg and their absolute value stays at 3.0, their relative VO2 max rises to about 37, roughly 11% higher, without any change in their heart or muscles.

That gain is real for everyday life, because you carry less weight up every hill and staircase. When you compare two tests across a period of weight change, look at absolute VO2 max as well where your report gives it, so you can tell how much of the change came from training and how much from body weight.

How VO2 Max Changes With Age

VO2 max declines with age, and the decline speeds up later in life. In the Baltimore Longitudinal Study of Aging, which followed 810 healthy adults aged 21 to 87 for a median of about 8 years, peak VO2 fell by about 3 to 6% per decade in people in their 20s and 30s and by more than 20% per decade from their 70s, at every level of self-reported activity ^[12].

Training still raises VO2 max at older ages. In a meta-analysis of 41 trials with more than 2,100 sedentary adults aged 60 and over, endurance training raised VO2 max by about 16% compared with control groups ^[9]. Starting later still moves the number, and a higher starting point gives you more room before the decline affects daily life ^[13].

Putting It Together

Improving VO2 max comes down to an easy aerobic base, one or two hard interval sessions a week, two strength days, and 8 to 12 weeks of consistency. Measure at the start, retest at the end, and treat a change of more than about 5% as progress worth keeping.

Related Articles

• VO2 Max Testing Near Me: Where to Get a Test and What It Costs

• Introducing the VO2 Max Test at Mito: Measure Your Fitness and Find Your Training Zones

• VO2 Max by Age: Charts for Men and Women and What Counts as Good

• Zone 2 Heart Rate by Age: Chart, Formulas and How to Measure Yours

• Apple Watch and Garmin VO2 Max Accuracy: How Close Is Your Watch to a Lab Test?

• Book a VO2 Max Test

Resources

1. Bassett DR, Howley ET. Limiting factors for maximum oxygen uptake and determinants of endurance performance. Med Sci Sports Exerc. 2000;32(1):70-84.

2. Mandsager K, et al. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Netw Open. 2018;1(6):e183605.

3. Piercy KL, et al. The Physical Activity Guidelines for Americans. JAMA. 2018;320(19):2020-2028.

4. Helgerud J, et al. Aerobic high-intensity intervals improve VO2max more than moderate training. Med Sci Sports Exerc. 2007;39(4):665-671.

5. Milanović Z, Sporiš G, Weston M. Effectiveness of high-intensity interval training and continuous endurance training for VO2max improvements: a systematic review and meta-analysis of controlled trials. Sports Med. 2015;45(10):1469-1481.

6. Weston KS, Wisløff U, Coombes JS. High-intensity interval training in patients with lifestyle-induced cardiometabolic disease: a systematic review and meta-analysis. Br J Sports Med. 2014;48(16):1227-1234.

7. Bacon AP, et al. VO2max trainability and high intensity interval training in humans: a meta-analysis. PLoS One. 2013;8(9):e73182.

8. Scribbans TD, et al. The effect of training intensity on VO2max in young healthy adults: a meta-regression and meta-analysis. Int J Exerc Sci. 2016;9(2):230-247.

9. Huang G, et al. Controlled endurance exercise training and VO2max changes in older adults: a meta-analysis. Prev Cardiol. 2005;8(4):217-225.

10. Montero D, Lundby C. Refuting the myth of non-response to exercise training: ‘non-responders’ do respond to higher dose of training. J Physiol. 2017;595(11):3377-3387.

11. Bouchard C, et al. Familial aggregation of VO2max response to exercise training: results from the HERITAGE Family Study. J Appl Physiol. 1999;87(3):1003-1008.

12. Fleg JL, et al. Accelerated longitudinal decline of aerobic capacity in healthy older adults. Circulation. 2005;112(5):674-682.

13. Strasser B, Burtscher M. Survival of the fittest: VO2max, a key predictor of longevity? Front Biosci (Landmark Ed). 2018;23(8):1505-1516.

Frequently asked questions

Why is my VO2 max going down?

The most common reasons are training less than before, gaining weight, and age. VO2 max is usually reported per kilogram of body weight, so extra weight lowers it even when your heart and muscles have not changed, and peak aerobic capacity declines with every decade of adult life.

Can walking improve VO2 max?

Brisk walking is aerobic training, and for people starting from a low fitness level it is a reasonable way to begin. Fitter people usually need harder efforts, such as intervals, to keep improving, because easy training alone tends to stop moving the number.

How often should I retest VO2 max?

Test once before a training block and again after 8 to 12 weeks. Retesting more often mostly measures day-to-day variation, since changes of less than about 5% between tests are within normal noise.

Is a higher VO2 max linked with living longer?

In large studies, higher cardiorespiratory fitness is associated with lower all-cause mortality, with low fitness carrying a risk comparable to smoking or diabetes. These are associations from observational data, not proof that raising your own number changes your risk.