How to Increase VO2 Max with Smarter Training
Dr Alex Trevatt23 September 2026Updated 28 September 2026
Improving VO2 max is not simply a matter of running harder. Easy aerobic work, higher-intensity intervals, recovery and consistent training all contribute, but the right mix depends on current fitness, health, training history and the activity being performed.
VO2 max is also a measurement that needs context. A laboratory result and a wearable estimate are not interchangeable, and a relative score can change when body mass changes even if absolute oxygen use does not. The practical goal is to use the best available information to set a sustainable training dose, then judge the trend rather than chasing a single number.
Table of Contents
- Why Most VO2 Max Advice Leaves Gains on the Table
- What VO2 Max Really Measures and Why It Matters
- The Interval Sessions That Actually Drive VO2 Max Gains
- Building Smarter Training Zones from Zone 2 to Zone 5
- Testing Your VO2 Max and Reading the Results
- Fuelling and Recovery Strategies That Protect Your Gains
- Tracking Progress and Adjusting Your Plan Over Time
Why Most VO2 Max Advice Leaves Gains on the Table
Generic advice often presents one interval format as the answer. In reality, the same pace can be a controlled aerobic interval for one person and an unsustainable sprint for another. Someone returning from inactivity also needs a different starting point from a well-trained runner or cyclist.
High-intensity interval training can improve cardiorespiratory fitness. A 2024 umbrella review included 24 systematic reviews, 429 primary studies and almost 13,000 participants. It found improvements compared with no exercise and, in many analyses, moderate continuous training. The authors also judged much of the review evidence to be of moderate to critically low methodological quality. That supports interval training as a useful option, not a guarantee that one protocol is best for everyone.
A beginner-friendly discussion of VO2 max in the UK may help explain the terminology. It should not replace individual screening or evidence-based programming.
Why intensity accuracy limits progress
Intervals need to be hard enough to create a strong aerobic demand and controlled enough to repeat with good technique. Starting too quickly can turn the first effort into an anaerobic sprint and reduce the quality of everything that follows.
A recent systematic review of time spent near VO2 max found that work intervals lasting at least two minutes generally produced more time near maximal oxygen uptake than shorter formats. The authors also reported substantial variation and noted that the link between time near VO2 max and long-term adaptation still needs more study. A secondary article comparing VO2 max and lactate-threshold sessions offers practical examples, but the scientific review is the stronger evidence source.
Heart rate lags behind effort, especially early in an interval. Pace, power, breathing, perceived exertion and session repeatability should therefore be considered together. A heart-rate percentage is a guide, not a target that must be forced immediately.
Practical rule: Finish the planned work with similar form and output across repetitions. If the first interval makes the remaining session collapse, the opening effort was probably too aggressive.
What VO2 Max Really Measures and Why It Matters
VO2 max is the highest rate at which the body can take in, transport and use oxygen during intense exercise. It is often reported relative to body mass in millilitres of oxygen per kilogram per minute, written as ml/kg/min. An explanation of VO2 max for athletes describes how this differs from pace or lung capacity alone.
Cardiorespiratory fitness reflects the integrated response of the lungs, heart, circulation, blood and working muscles. It matters to endurance performance, but it is also relevant to health. The broader aim for most adults should still include the NHS physical activity guidance: at least 150 minutes of moderate activity or 75 minutes of vigorous activity per week, plus strength work on at least two days, adjusted for fitness and health.
Relative and absolute values tell different stories
Absolute VO2 is normally expressed in litres per minute. Relative VO2 divides that amount by body mass. Relative values are useful in weight-bearing sports, but the denominator matters: losing body mass can raise a relative score without the same change in absolute oxygen use, while gaining useful muscle can lower it.
Age, sex, exercise mode, training status, test protocol and clinical context all affect interpretation. Population tables are descriptive, not pass-or-fail thresholds. Comparing a treadmill result with a cycle result, or one wearable algorithm with another, can create an apparent change that is partly methodological.
A VO2 Max Test uses graded exercise and respiratory gas analysis to measure oxygen use. It can also help identify physiological transition points for training. This makes cardiorespiratory fitness more actionable than a generic age-based formula. For less formal cardio ideas, Thermo Recovery Wear fitness advice may prompt variety, but it is a commercial lifestyle page rather than the evidence source for the recommendations here.
The Interval Sessions That Actually Drive VO2 Max Gains
There is no single interval session that suits every person. The mode should be familiar and mechanically tolerable, the work bouts should create a severe but repeatable effort, and the recovery should allow useful work to continue.
People who have been inactive, have cardiovascular symptoms or risk factors, are pregnant, or have a medical condition should seek appropriate clinical advice before beginning maximal or near-maximal exercise. Chest pain, fainting, unexplained severe breathlessness or palpitations during training warrant medical assessment rather than a harder programme.
A controlled 4x4 structure
One researched format uses four 4-minute efforts separated by 3 minutes of active recovery. In a small randomised study of 40 healthy, moderately trained men, the group training at 90 to 95% of measured maximum heart rate improved VO2 max over eight weeks. The study is useful evidence for the protocol, but its narrow sample and three-session weekly schedule do not make that dose universally appropriate.
A cautious practical structure is:
- Warm up progressively for at least 10 minutes, including a few short increases in pace.
- Complete up to four controlled 4-minute efforts, with easy active recovery between them.
- Use pace or power that allows the work to remain repeatable. Heart rate may rise into a high range later in each effort rather than immediately.
- Cool down gradually.
Newer athletes can begin with fewer repetitions, shorter work bouts or a lower-impact mode. Progress only when the session is repeatable and recovery is acceptable. Maximal training is not required every time an athlete wants an aerobic stimulus.
Choosing density over drama
Running intervals are specific for runners but add impact and tendon load. Cycling, rowing or an incline treadmill may allow a strong cardiovascular stimulus with a different mechanical cost. Transfer between modes is not identical, so the choice should reflect the goal and injury history.
- Running: sport-specific for runners, with higher impact.
- Cycling: easier to control mechanically, but less specific to running economy.
- Longer intervals: usually create more sustained oxygen demand, but need careful pacing.
- Short intervals: can still be effective, particularly when accumulated into a well-designed session.
More intensity is not automatically better. One quality interval session per week may be enough for someone who is new to structured high-intensity work. Experienced athletes may tolerate more, but the decision belongs within the total training load, not in isolation.
Building Smarter Training Zones from Zone 2 to Zone 5
Zone systems are useful shorthand, but different organisations and devices divide intensity differently. A five-zone watch model, a three-zone physiological model and zones based on cycling power will not always line up.
Easy aerobic training should usually feel sustainable and conversational. Threshold work is harder and sits near the highest intensity that can be sustained for a prolonged period. VO2 max intervals are more severe and are normally performed as repeated bouts because the intensity cannot be maintained continuously.
What each zone is trying to achieve
In a common five-zone model:
- Zone 2: easy aerobic volume that can usually be repeated with modest recovery cost.
- Zone 3: steady or tempo work, depending on the system being used.
- Zone 4: work around a higher threshold, demanding but more sustainable than VO2 max intervals.
- Zone 5: severe-intensity intervals intended to challenge high-end aerobic power.
These labels should not be tied to a universal lactate value or percentage of age-predicted maximum heart rate. Measured thresholds, breathing, perceived exertion, pace or power and the ability to repeat the session give a more complete picture. See training zones and exercise intensity for a fuller explanation.
Sequencing the week
Place demanding sessions far enough apart that each can be completed well. Easy aerobic work, rest and strength training then fit around the main quality sessions. The balance varies with sport, experience and life stress.
A 5 km runner may combine easy mileage, threshold work and a VO2-focused session. A cyclist may accumulate more low-impact volume but still needs recovery from demanding intervals. A person exercising for health can improve fitness without adopting an athlete’s volume or intensity.
Routine matters because the best programme is ineffective when it cannot be followed. A page on routine building with Longwelle may help organise training around daily life, though it is not clinical guidance. The commercial ANALYSE Longevity Test Bundle is also a booking offer rather than evidence for a particular testing frequency.
Testing Your VO2 Max and Reading the Results
A laboratory or mobile metabolic test and a wearable estimate answer different questions. Direct respiratory gas analysis measures the response during a graded exercise test. A wearable estimates a value from heart rate, speed, power and a proprietary model.
An NHS research summary on remote VO2 max measurement describes research into remote estimates; it does not establish that a consumer wearable is interchangeable with cardiopulmonary exercise testing.
What laboratory testing adds
During a graded test, workload rises while oxygen uptake, carbon dioxide production, ventilation and heart rate are monitored. The protocol and exercise mode matter. A valid maximum also depends on effort and on the criteria used by the testing service.
The result can help establish a baseline, identify transition points and translate them into heart-rate, pace or power ranges. It should still be interpreted alongside symptoms, medical history, training and the quality of the test. A performance test does not diagnose every cause of breathlessness or fatigue.
Where wearables still earn their place
Wearables are valuable because they collect frequent, real-world data. Their estimates can be affected by sensor contact, movement, temperature, device settings, exercise mode and algorithm changes.
| Feature | Respiratory gas test | Wearable estimate |
|---|---|---|
| Oxygen uptake | Measured from breathed gases | Estimated from indirect signals |
| Thresholds | May be identified from respiratory data | Usually inferred |
| Best use | Baseline and individual calibration | Frequent trend monitoring |
| Main limitation | Requires a structured exercise test | Device and algorithm uncertainty |
Use the same device and broadly comparable conditions when judging a trend. Do not treat one low reading as proof of lost fitness. Illness, heat, poor sleep, fatigue, altered terrain and sensor error can all contribute. The guide to whether VO2 max testing is worth it discusses when measured data may change a training decision.
Fuelling and Recovery Strategies That Protect Your Gains
High-intensity training is difficult to execute when energy intake is chronically inadequate. Carbohydrate availability can affect the ability to sustain hard work, while protein, total energy, hydration and micronutrient sufficiency support recovery. Exact requirements depend on session duration, body size, wider diet and goal; a universal grams-per-hour prescription is not necessary for every interval session.
Body composition changes the denominator
Because relative VO2 max is divided by body mass, weight change can alter the score. That does not mean weight loss is automatically the correct way to improve performance. Aggressive restriction may reduce recovery, training quality, bone health and lean tissue.
DEXA can measure bone mineral density and estimate fat mass and lean soft tissue. It uses ionising radiation, and lean soft tissue is not the same as directly measured skeletal muscle. The NHS guide to what happens during a DEXA scan explains the clinical bone-density procedure.
The linked government consultation on non-medical DEXA discusses sports and wellness use, but the current government position remains that purely non-medical use is prohibited. Telomyx operates a medical pathway: every request is screened through a medical questionnaire, requires referral and must be individually justified by an entitled practitioner. Interest in performance or body composition can prompt an enquiry, but it does not guarantee exposure; unsuitable or unjustifiable requests are not scanned.
Recovery should support adaptation, not just comfort
Sleep, adequate food, appropriate easy days and sensible spacing between hard sessions are the foundations. Resting heart rate, heart-rate variability and perceived recovery may add context, but there is no universal percentage change that should dictate training for every person.
Recovery products should not distract from those basics. Athletes considering THC-free CBD for fitness should recognise that this is a commercial page, that evidence for performance recovery is limited, and that supplements can interact with medicines or carry contamination risk. Competitive athletes also need to consider their sport’s anti-doping rules.
Tracking Progress and Adjusting Your Plan Over Time
Progress can appear as a higher measured VO2 max, more pace or power at a similar physiological strain, better repeatability, or improved recovery between efforts. No single signal captures all of these.
Track a small set of useful measures:
- completed training and any missed sessions;
- pace or power across every repetition, not only the fastest;
- heart rate alongside perceived exertion;
- sleep, illness, symptoms and unusual fatigue;
- body mass only when it is relevant and interpreted carefully.
Retesting should occur when the result is likely to change a decision and enough training has accumulated to make comparison meaningful. Use the same exercise mode, similar preparation and a comparable protocol where possible. Fixed short retest schedules can exaggerate normal measurement variation.
A practical review rhythm
Review the week first, then the training block:
| Review point | Question | Possible response |
|---|---|---|
| After each hard session | Were pace, power and technique repeatable? | Reduce the opening intensity if later efforts collapse |
| Weekly | Is fatigue rising while output falls? | Add recovery or reduce non-essential load |
| Every few weeks | Is the overall trend improving? | Maintain, progress one variable or revise the plan |
| At a planned retest | Are conditions and protocol comparable? | Recalibrate zones only when the result is credible |
A plateau does not automatically call for harder intervals. The limitation may be inconsistent easy volume, poor recovery, inadequate fuelling, inaccurate zones, illness or a programme that is too demanding to sustain.
Telomyx provides mobile VO2 max testing in North West England, with DEXA and resting metabolic rate services available through their appropriate pathways. Visit Telomyx for current service information. Objective testing can improve a plan when the result is interpreted carefully and used alongside the person’s health, goals and training history.
This article is for general educational purposes only. It does not constitute medical, dietary or exercise advice and is not a substitute for individual assessment by an appropriately qualified professional.
