How Can You Improve Your VO2 Max? A Sports Scientist Answers
Introduction
This piece is part of the VO2max series, where an AI interviewer speaks with a qualified sports scientist about real-world strategies for improving cardiorespiratory fitness. The goal is to present expert insights in a conversational format while grounding the discussion in established physiology and scientific literature.
Below is the full interview transcript, lightly edited for readability but preserving the expert’s original explanations and perspectives.
AI: You focus a lot on VO2 Max in your work. Why is it such a central marker for you?
Sports Scientist: VO2 Max is the gold-standard biomarker of overall health. We don’t currently have a mainstream, universally accepted “health score” for the general population, but VO2 Max is the closest thing we have. It tells you how your cardiovascular, pulmonary, and muscular systems are functioning together. My whole website, channel, and blog revolve around VO2 Max because it’s one of the most sensitive indicators of how well you’re actually doing health-wise.
AI: If someone is starting from scratch and wants to improve their VO2 Max, where should they begin?
Sports Scientist: The first place to look is body fat percentage. People forget that fat mass is still mass. Your heart must pump blood around whatever total mass you carry. Higher body fat increases the circulatory demand without providing functional benefit to movement. Fat mass simply isn’t helpful when it comes to VO2 Max, so the first step is assessing whether your body fat percentage sits within a healthy range.
(Literature support: Lower body fat is consistently correlated with higher VO2 Max in population studies; see Lee et al., Medicine & Science in Sports & Exercise, 2016.)
AI: After body composition, what’s the next major consideration?
Sports Scientist: Muscle mass—both building it and maintaining it. Working muscle mass directly promotes a higher VO2 Max because muscle tissue demands oxygen. The more functional muscle you have, the more your cardiovascular and pulmonary systems must adapt to deliver oxygen efficiently. There’s clear evidence showing a positive correlation between muscle mass and VO2 Max. If your muscle mass is low, the whole system underperforms.
(Literature support: Strong associations between fat-free mass and VO2 Max are well-documented; see Kim et al., European Journal of Applied Physiology, 2020.)
AI: What kinds of training approaches do you typically recommend to improve VO2 Max?
Sports Scientist: You need a balance. On one side, you need mesocycled strength training to allow muscle mass to grow. On the other, if you want to boost VO2 Max fast, interval-style work is incredibly effective. HIIT, interval training, or fartlek training—anything with high-on, short-off bursts—pushes the pulmonary and cardiovascular systems to adapt rapidly. These sessions create the stress that forces oxygen delivery systems to improve.
(Literature support: HIIT is shown to be superior to steady-state training for VO2 Max improvements in many populations; see Milanović et al., Sports Medicine, 2015.)
AI: You mentioned earlier that hydration is often overlooked. How does hydration influence VO2 Max?
Sports Scientist: Hydration is fundamental. We’re roughly 65–70% water, depending on age and body composition. That includes the interstitial space, pulmonary circuit, blood plasma—every level of the system. To transport oxygen effectively, you need the right blood pressure and healthy blood viscosity. Dehydration thickens the blood and compromises oxygen delivery. If your goal is to maximise VO2 Max, you need to keep the circulatory system functioning efficiently, and water plays a major role in that.
(Literature support: Dehydration impairs cardiovascular function and VO2 Max; see Sawka & Noakes, Journal of Applied Physiology, 2007.)
AI: And how does nutrition play into this?
Sports Scientist: Nutrition is key, especially understanding fats. Not all fats are equal. Low-density lipoproteins (LDL) are larger and more problematic. They contribute to circulatory restriction, which directly affects oxygen delivery down at the tissue level. In contrast, high-density lipoproteins (HDL) help clear the circulatory system and support cardiovascular health.
People often assume they should avoid fats entirely, but many fats are essential. Then you have protein, which makes up a huge amount of our structural tissue—from collagen to muscle fibres. And carbohydrates are the fuel source that lets you actually utilise your VO2 Max. Without adequate carbohydrates, you simply don’t have the energy to perform at the intensities needed to stimulate improvement.
A balanced diet—protein, fats, and carbohydrates in correct proportion—is fundamental.
(Literature support: HDL and LDL have well-established opposing roles in cardiovascular efficiency; see Krauss et al., Circulation, 2020.)
Conclusion
Improving VO2 Max requires a multi-dimensional approach: managing body fat, building muscle, training intelligently, staying hydrated, and maintaining proper nutrition. As this conversation shows, cardiorespiratory fitness isn’t just about running or cycling harder—it’s about optimising the whole human system.
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