One of the most well-known measures of aerobic fitness is VO2 max. It is closely related to cardiovascular efficiency, endurance performance, and general metabolic health and refers to the maximum amount of oxygen your body can use during vigorous exercise.
Although genetics, training, and age all have a significant impact on VO2 max, one of the most pronounced differences observed in population studies is between men and women. Men typically have higher VO2 max scores than women, even among trained athletes. However, why?
The physiological and hormonal variables that affect VO2 max by gender will be discussed in this article, along with the practical implications of these variations for performance, training, and health.
What Is VO2 Max?
VO2 max stands for “Maximal oxygen uptake”. During peak exercise, it is the amount of oxygen (measured in millilitres) that the body can absorb per kilogramme of body weight per minute. Your heart, lungs, and muscles are more effective at supplying and utilising oxygen during physical activity if your VO2 max is higher.
It is more than just a metric for athletes. It is becoming more widely acknowledged that VO2 max is a reliable indicator of long-term health outcomes, such as metabolic function, cardiovascular disease, and even lifespan.
Average VO2 Max Scores: Men vs. Women
Compared to women of the same age and fitness level, men typically have a VO2 max that is 15–30% higher. A healthy female may score closer to 35–40 mL/kg/min, whereas a healthy, untrained male in his 20s may have a VO2 max of 40–45 mL/kg/min.
The disparity still exists among top endurance athletes:
- 70–85+ mL/kg/min for male elite endurance runners
- 60–75 mL/kg/min for female elite endurance runners
However, this disparity is based on biological differences rather than just effort or training history.
Why Do Men Typically Have Higher VO2 Max?
1. Greater Stroke Volume and Heart Size
Men’s hearts can pump more blood with each beat because they typically have larger hearts and larger stroke volumes. During exercise, this leads to increased cardiac output and improved oxygen delivery to muscles.
2. Elevated levels of haemoglobin
The oxygen-carrying protein in red blood cells is called haemoglobin. Men typically have haemoglobin concentrations that are 10–15% higher than those of women. This gives them a vital advantage during high-intensity exercise by enabling them to carry more oxygen per unit of blood.
3. Increased Lean Muscle Mass
A common way to express VO2 max is in relation to body weight. Men tend to use more oxygen per kilogramme because they have more lean muscle and less body fat. Muscle tissue is more metabolically active and requires more oxygen than fat, which contributes to a higher VO2 max.
4. Pulmonary Capacity and Lung Size
During prolonged exercise, men’s larger lungs and airways can enhance oxygen uptake and lessen respiratory fatigue. Under stress, this enables more effective gas exchange.
What Role Do Hormones Play?
Numerous physiological systems involved in energy metabolism and endurance are influenced by sex hormones.
Oestrogen may enhance lipid metabolism and fat oxidation during exercise and has some cardio-protective effects in women. It can affect muscle mass and recovery, though, and it also tends to encourage increased fat storage.
More common in men, testosterone promotes the growth of muscles, the synthesis of red blood cells, and total power output, all of which raise VO2 max values.
Although the overall effect on VO2 max is minimal, hormonal changes during the menstrual cycle can also affect a woman’s perceived effort, endurance, and recovery.
Does This Mean Men Are “Fitter”?
Not always. Although VO2 max is one indicator of cardiovascular capacity, it is not a complete picture.
For example:
- Absolute numbers are less important than relative performance. An untrained man with a higher baseline VO2 max might not perform as well as a highly trained woman with a VO2 max of 60 mL/kg/min.
- Performance is influenced by a number of factors that VO2 max cannot measure, including efficiency, mental toughness, lactate threshold, and movement economy.
- Due to superior fatigue resistance and pacing techniques, women can sometimes outperform men in ultra-endurance events, where the gender gap frequently closes.
Can Women Improve VO2 Max Just as Much as Men?
Indeed. Both sexes can greatly increase their VO2 max through organised endurance training, even though men may begin with a higher baseline because of physiological differences. Depending on age, training intensity, and fitness level, the usual improvement range is 10–25% over a few months.
The following are the best training techniques:
- Training in Zone 2: Long, steady-state workouts to increase aerobic capacity
- Interval training: brief, high-intensity workouts that test one’s maximum potential
- Tempo efforts: Lactate-clearing threshold exercises
- Cross-training: Exercises that lower the risk of injury, such as swimming, rowing, or cycling
Both men and women experience training adaptations, such as increased capillary networks, mitochondrial density, and stroke volume. Progressive overload and consistency are crucial.
VO2 Max and Health Risk
Crucially, VO2 max is a strong predictor of longevity and health, not just a performance metric.
Low VO2 max values are linked to an increased risk of:
- Cardiovascular disease
- Type 2 diabetes
- Cognitive decline
- Early mortality
Regardless of gender, research indicates that increasing VO2 max by even modest amounts can dramatically lower your risk of developing chronic illness.
Regular VO2 max testing may help women in particular detect early fitness declines, particularly during life transitions like pregnancy, menopause, or the healing process after illness.
VO2 Max Testing for Women and Men
Although fitness tests and wearable technology can be used to estimate VO2 max, laboratory-based testing is the gold standard for reliable results.
When taking a VO2 max test:
- You work out more intensely on a bike or treadmill
- You put on a mask that tracks your carbon dioxide and oxygen intake
- Your heart rate, respiratory rate, and oxygen utilisation are recorded in real time
Along with information that can direct training zones, recovery schedules, and health risk assessments, the results provide you with an accurate assessment of your cardiovascular capacity.
Final Thoughts
Although men tend to have higher VO2 max values because of biological and physiological advantages, performance, potential, and fitness are not defined by the metric alone. With the right training, women can raise their VO2 max just as successfully, and even a small increase can have a big impact on their health.
Health professionals, athletes, and regular fitness enthusiasts can set reasonable goals, customise their training, and maintain focus on long-term progress rather than just the number on the page by knowing how gender influences VO2 max.
References
- Sex differences in oxygen uptake during exercise: role of haemoglobin concentration and blood volume
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9105160/ - Biological sex differences in VO2 max: a contemporary review of mechanisms
https://www.sciencedirect.com/science/article/pii/S2667137921000229 - American College of Sports Medicine – VO2 Max Norms
https://www.acsm.org/read-research/resource-library
