VO2 max is trainable — but has a ceiling

Research consistently shows that VO2 max can be improved through training, typically by 10–20 percent in untrained individuals and 5–10 percent in those already moderately fit. Highly trained athletes show smaller gains because they are already operating closer to their genetic ceiling. High intensity interval training (HIIT) and sustained aerobic volume both contribute to VO2 max improvements, but the relative contribution depends on the individual’s current fitness level and training history, which is exactly why baseline testing matters.

VO2 max predicts more than athletic performance

A growing body of research has established VO2 max as one of the strongest independent predictors of all-cause mortality, more predictive than blood pressure, cholesterol, or body weight. A landmark study published in JAMA Network Open found that low cardiorespiratory fitness carried a higher relative risk of death than smoking, diabetes, or hypertension. This has shifted the clinical conversation around VO2 max testing from purely athletic to broadly medical. Knowing your VO2 max is not just useful for race day, it is a meaningful marker of long-term health.

Lactate threshold matters as much as VO2 max

More recent sports science research has highlighted that lactate threshold, the exercise
intensity at which lactate begins to accumulate faster than the body can clear it, may be an even more powerful predictor of endurance performance than VO2 max alone. Two athletes with identical VO2 max values can have very different performance outcomes if their lactate thresholds occur at different percentages of their maximum.

This is why modern VO2 max testing, including cardiopulmonary exercise testing (CPET) goes beyond measuring peak oxygen consumption. A comprehensive test identifies both the first lactate threshold (the point where breathing first becomes laboured) and the second lactate threshold (the point beyond which effort becomes unsustainable), giving a precise picture of the training zones that will produce the most adaptive response.

Heart rate zones based on feeling are not good enough

Most recreational athletes train using heart rate zones derived from age-based formulae such as 220 minus age. Research shows these formulae carry a standard deviation of approximately 10–12 beats per minute, meaning for a significant proportion of athletes, their calculated zones are meaningfully wrong. Training consistently in the wrong zones is one of the most common reasons athletes plateau, overtrain, or fail to develop the aerobic base they are working towards. A VO2 max test replaces population averages with your actual physiology.

WHAT A VO2 MAX TEST ACTUALLY INVOLVES

A cardiopulmonary exercise test (CPET), the clinical gold standard for VO2 max measurement is conducted on a treadmill or cycle ergometer while the patient breathes through a mask connected to a metabolic analyser. The test uses a graded protocol: intensity increases incrementally every one to three minutes while the analyser measures oxygen consumption, carbon dioxide output, ventilation, and heart rate in real time.

The test typically lasts between 8 and 15 minutes. It is uncomfortable at peak intensity, that is by design, as a true VO2 max requires maximal effort, but it is safe when conducted with appropriate medical oversight. At UPANDRUNNING, all CPET testing is supervised by Dr. Zahra Alizadeh, a Sports Medicine Specialist with specific expertise in exercise stress testing and performance optimization.

Following the test, results are interpreted and presented as:

• VO2 max — your absolute aerobic ceiling
• VT1 and VT2 — your first and second ventilatory thresholds,corresponding to your aerobic and anaerobic threshold training zones
• Heart rate at each threshold — your personalised heart rate training zones based on
  actual physiology, not formula
• Economy data — how efficiently your body uses oxygen at various intensities
• Respiratory exchange ratio — indicating substrate utilisation (fat vs carbohydrate burning) at different intensities

HOW ENDURANCE ATHLETES USE VO2 MAX TESTING IN PRACTICE

Establishing precise training zones

The most immediate application is replacing generic heart rate zones with physiologically accurate ones. Once you know the exact heart rate at which your lactate thresholds occur, every training session can be targeted precisely, whether the goal is building aerobic base, improving threshold capacity, or developing peak speed. This is the foundation of polarised training, the approach now used by most elite endurance coaches, which relies on knowing exactly where Zone 2 ends and Zone 3 begins.

Identifying limiters and tracking adaptation

A VO2 max test reveals not just your ceiling but how you are approaching it. An athlete whose VO2 max is high but whose lactate thresholds are low relative to their maximum has significant room to improve performance without any increase in their aerobic ceiling, the limiter is threshold capacity, not peak oxygen consumption. Retesting every three to six months allows athletes and coaches to track whether training adaptations are occurring as expected and adjust the programme accordingly.

Nutrition and fuelling strategy

The respiratory exchange ratio data from a VO2 max test reveals the intensity at which your
body transitions from primarily burning fat to primarily burning carbohydrate. This is
enormously useful for race nutrition planning — particularly for ultra-endurance events where
fat oxidation capacity is a critical performance determinant. Athletes who know their fat-
burning ceiling can train specifically to extend it, and can plan fuelling strategies around the
actual metabolic demands of their target event.

Medical clearance and cardiac screening

For masters athletes, those over 35, and particularly over 45, a CPET performed with ECG
monitoring provides meaningful cardiac screening alongside performance data. Exercise-
induced arrhythmias, ST segment changes, and abnormal blood pressure responses that
may not be apparent at rest can be identified during a maximal effort test. For competitive
athletes training at high volumes in Dubai’s climate, this is both clinically prudent and
increasingly requested by race organisers for masters competitors.
Returning to training after illness or injury
Athletes returning from significant illness, surgery, or extended training breaks often face the
question of where to start. A VO2 max test provides an objective baseline that removes the
guesswork, and for post-COVID athletes in particular, CPET has emerged as a valuable tool
for identifying exercise intolerance and guiding a safe, evidence-based return to training.