Maximum oxygen uptake: the ceiling for endurance athletes?
Tim Noakes famously said in his book Lore of Running:
“Even with intensive training, maximal oxygen uptake only improves by an average of 5-15%. Obviously, the average person cannot achieve the maximal oxygen uptake of an elite athlete, no matter how much they train.
This idea has been a mainstay of exercise physiology since I was an undergraduate 25 years ago. Is everyone in agreement? Maximum oxygen uptake is one of the most important physiological characteristics of endurance athletes, and depends heavily on genetics. If you’re not happy with your values, well, “blame it on your parents.”
But how accurate is that statement?
Let’s put aside sedentary twin studies and short-term papers for a moment. What happens when we observe real athletes for extended periods of time and have them tested by exercise physiologists, who typically follow the same athletes year after year? Does the idea that maximal oxygen uptake is primarily untrainable still hold true? By observing real-life athletes, can we realistically expect how much maximal oxygen uptake will improve over time?
Understanding VO2 Max and its role in team sports
Before we dive in, let’s quickly review what VO2 max actually is and how important it is.
VO2 max is the total amount of oxygen a muscle takes up from the bloodstream per minute. It measures the overall strength of the aerobic system, reflecting oxygen supply (heart and lungs) and oxygen uptake (muscles). For endurance athletes, a high maximal oxygen uptake is critical because it allows the body to produce energy through aerobic exercise, prevents lactic acid buildup, and allows the athlete to remain energized for long periods of time.
Although maximal oxygen uptake is particularly important in endurance sports, its importance is not limited to endurance sports. In intermittent sports, such as team sports, maximal oxygen uptake plays a crucial role in recovery between high-intensity exercise. Even if the critical moments of a game are driven by anaerobic exercise, a strong aerobic system can shorten recovery time, allowing athletes to put in a greater effort during the game and recover more quickly between training intervals. This quicker recovery translates into higher quality training and race performance.
It is not surprising that the world’s best endurance athletes have extremely high values of maximal oxygen uptake (VO2 max). Interestingly, athletes in non-endurance sports also tend to exhibit high VO2 max values. See below for data that shows high VO2 max values in different sports.
The True Limit of Oxygen Maximum Uptake
Now, let’s talk about an often frustrating statement: maximal oxygen uptake can only be increased by 5-15% at most.
If you come to the lab with a maximal oxygen uptake (VO2 max) of 50 ml/kg/min, no matter how hard you train, the best you can do is only improve to about 57 ml/kg/min. This improvement, while significant, is still a far cry from what world-class athletes achieve. World class athletes typically achieve 75-85 ml/kg/min.
As many exercise physiologists have stated, the reality is that the genetic upper limit of maximal oxygen uptake may be determined from the outset. While training can increase your maximal oxygen uptake, there is only so much that can be done to raise it above the threshold. Ultimately, factors such as genetics, age and talent determine people’s ability to optimize this key metric. But don’t be discouraged-even a small increase in maximal oxygen uptake can have a profound effect on endurance performance, allowing you to train harder and recover faster.
Conclusion: genetic ceiling and room for improvement
The notion that VO2 max is essentially untrainable is much more subtle than it might seem at first glance. While genetic factors may limit your room for improvement, with proper training and consistency, even modest increases in VO2 max can yield impressive results, especially in terms of recovery and overall endurance.
So while you may not be able to achieve the VO2 max levels of elite athletes, you can still see meaningful improvements that will enhance athletic performance. With focused effort and the right strategy, VO2 max training can lead to impressive gains – even if it’s not the dramatic increases we expect. For more insights on optimizing your training, check out our guide to interpreting HRV trends in athletes.
For world-class female athletes, who consume between 65-75 milliliters of oxygen per minute per kilogram of body weight, increasing your maximal oxygen uptake from 50 to 57 won’t make you stand out in most local competitions, let alone win the big ones! This “rule of thumb” is backed by science. A study on maximal oxygen uptake in twins concluded that genetics accounted for 72-74% of the difference in maximal oxygen uptake. Even after accounting for “exercise participation”, genetics explained 57% to 63% of the variance. It is this research that reinforces our belief that maximal oxygen uptake is largely genetically determined and that gains through training are usually small.
A good example of this is my experience of being tested for maximal oxygen uptake during my undergraduate degree in exercise physiology. My result was 62 ml/kg/min – not amazing, but pretty good considering I’ve been training hard in the pool for the last ten years. 62 ml/kg/min puts me in the “well-trained” range, which I thought was good enough to keep me stable. I thought it was enough for me to maintain a consistent, but not exceptional, athletic performance. It wasn’t until years later that I decided to test again at a newly established lab in Boulder, Colorado.
To my surprise, my maximal oxygen uptake had dropped to 49 mL/kg/min! Even though I was still competing in triathlons at the time and was not yet old enough to explain this dramatic drop, my maximal oxygen uptake had dropped by almost 20%! Instead of getting discouraged, I started thinking: if my maximal oxygen uptake could go down this much, could it also go up?
Fortunately, as an exercise physiologist and endurance coach, I have the ability to delve into how to increase maximal oxygen uptake through training. I spent years testing athletes repeatedly while closely tracking their training loads to see how maximal oxygen uptake changed. The result? Much more than the typical 5-15% improvement I had previously expected.
One athlete’s case stood out as an example of how real-world training can lead to extraordinary VO2 max increases. I began working with an ambitious intermediate athlete. He had tried a variety of intensity training programs, but despite trying very hard, he was never able to break through the bottleneck. These programs typically consisted of 3-4 months of intensive training leading up to a key event, focusing on high intensity interval training at both VO2 and threshold levels. The high intensity training period is followed by months of unregulated recovery.
When I first tested this athlete, his maximal oxygen uptake was only 53 ml/kg/min. Based on what we “know,” I might have thought, “This guy isn’t untrained, but with a maximal oxygen uptake of only 53, it’s going to be a little difficult for him to qualify for the Ironman World Championship.” Objectively speaking, most male athletes in his age group who reach this level have a maximal oxygen uptake closer to 65.
But this is just the beginning of his journey. Through tailored training and relentless hard work, his maximal oxygen uptake will continue to prove that the limits are far higher than he ever imagined.
-70 ml/kg/min. Even at lower levels, this represents a 22% increase in maximal oxygen uptake (VO2 max) (from an already high level)! In hindsight, should I have just told him, “No way, champ”? Fortunately, we didn’t ……
Three years later, this athlete’s VO2 max had increased by a whopping 40% from 53 ml/kg/min to 74 ml/kg/min, jumping from average to elite levels. During this time, he realized his dream of competing in the Ironman World Championship.
Figure 2 shows the steady improvement in this athlete’s maximal oxygen uptake (VO2 max) over each year of training ……
Figure 2.Over the course of three years, the athlete’s VO2 max increased from an intermediate level of 53 ml/kg/min to an elite level of 74 ml/kg/min, while realizing his goal of competing in the Ironman World Championship.
So what is the secret behind this remarkable transformation (which far exceeds typical research findings)?
While much of the literature on improving maximal oxygen uptake focuses on high-intensity training methods, specifically “maximal oxygen uptake interval training,” we chose a different approach. For this athlete, most of his training was centered around the aerobic threshold (the first lactate turning point – i.e., training at a lactate level of 1-2 mmol/L), which is far from the intensity required for maximal oxygen uptake.
We chose low-intensity, high-volume training as an effective strategy for increasing maximal oxygen uptake, based on the established link between training volume and cardiac stroke volume. A pivotal study conducted by Berbalk on cardiac morphology in athletes showed a significant near-linear relationship between training volume and total cardiac volume, as shown in Figure 3.
Figure 3. The relationship between training volume and cardiac stroke volume – the key factor influencing maximal oxygen uptake – supports the idea that it is training volume, not intensity, that plays a key role in cardiac adaptation. (Data from Berbalk study (2).)
Simply put, the total volume of the heart increases with training volume, not with intensity. This makes sense physiologically, as output per beat typically peaks at moderate intensities (~40-60% maximal oxygen uptake). However, as Berbalk’s data suggests, it takes a lot of training volume (i.e., many heartbeats) to bring about significant changes.
In addition to this, low-intensity, prolonged, low-intensity long-distance (LSD) training promotes beneficial peripheral adaptations.Harms and Hickson’s study showed that increased mitochondrial content (which is critical for oxygen processing in the muscles) was strongly correlated with the number of muscle contractions, rather than the intensity of the exercise. The more mitochondria there are, the more oxygen the muscle is able to extract and utilize, thus increasing endurance.
This low-intensity aerobic training is in stark contrast to methods previously employed by athletes. One of the most insightful aspects of current technology and data tracking is how much a coach can learn from an athlete’s training log. In this case, the athlete’s previous training regimen consisted primarily of threshold and maximal oxygen uptake training. The difference in the distribution of training intensity between his previous year (year 0) and his best performance in year 3 is shown in Figure 4.
Figure 4. the shift to a predominantly low-intensity aerobic training approach compared to the previous year is key to optimizing performance and developing the endurance required for high-level success.
This athlete’s performance was an amazing turnaround from his performance prior to working with me. Interestingly, the reduction in high intensity “VO2 work” resulted in a significant increase in his VO2 max.
Before we started working together, this athlete rarely trained in low-intensity zones, especially zones below 80% of heart rate max. The limited training he did during this time was primarily in preparation for more intense training. We made significant adjustments by increasing easy aerobic exercise (approximately 65-80% of maximal heart rate) and decreasing high intensity exercise (85-100% of maximal heart rate). Paradoxically, the reduction in “VO2 work” greatly increased his VO2 max!
Although the athlete did not have VO2 data prior to starting high intensity training, he remembers that his cycling power numbers improved rapidly at first, but then stagnated and stayed at that level. This stagnation is common among athletes who focus on high intensity (traditional “VO2 max”) training.
This is not to say that traditional VO2 max interval training (3-5 minutes at 95-100% of max heart rate with recovery times of about 1:1) is ineffective. They are certainly not useless, but they should be viewed as icing on the cake rather than base training. Athletes no longer show improvement in aerobic capacity when they reach high levels of aerobic efficiency. This is evident when the athlete no longer experiences a VO2 “plateau” in testing, despite the increased workload. When an athlete is unable to reach this plateau period, the addition of a small number of VO2 max intervals can help reach the last few milliliters per kilogram per minute of VO2 max. However, these lifts usually occur later (e.g., from 70 ml/kg/min to 74 ml/kg/min) rather than earlier (e.g., from 53 ml/kg/min to 70 ml/kg/min) because most of the lifts are achieved during sustained aerobic exercise.
According to @alan_couzens, it is a well-documented phenomenon that athletes who focus on high-intensity (traditional “maximal oxygen uptake”) training typically stagnate.
This shift in training style has interesting implications for athletes who engage in anaerobic exercise. Traditional VO2 max interval training tends to be counterproductive for athletes who focus on speed and strength because they prioritize lactate tolerance over lactate production in type II fibers – focusing more on endurance than speed. By focusing on developing aerobic capacity at the lower end of the intensity spectrum, speed and power athletes can maintain Type II fiber adaptations that are directly related to their sport. It also enhances the aerobic capacity of the athlete’s Type I “recovery fibers,” which play a lesser role in power generation during anaerobic exercise, but are critical for rapid recovery between high-intensity workouts.
I’ve worked with a number of elite sprint cyclists and have seen this approach first hand: their endurance training is less intense, but their sprints are extremely fast. This “polarized” training model seems to benefit athletes by allowing them to rapidly increase their anaerobic capacity while also utilizing their aerobic energy systems for rapid recovery.
Is this increase in VO2 max representative?
A 40% increase in VO2 max like this is one of the most dramatic improvements I’ve seen, but it’s not common. However, based on my experience testing and observing athletes over the past decade, the lifts from sustained aerobic training are usually greater than the typical 5-15% mentioned in the literature.
In fact, when I analyzed the average response of a large number of athletes to training as well as VO2 and long-term training data, I found that a long-term, high-intensity training program resulted in an increase in the average from 54 ml/kg/min to 67 ml/kg/min (a 24% improvement).
On the other hand, with a short-term, high-intensity training program, maximal oxygen uptake (after 4-6 weeks) typically only increased by 63 ml/kg/min (approximately 16% improvement).
While a 40% increase in maximal oxygen uptake (VO2 max) may not be common, it is certainly achievable in some cases. In my experience, an improvement of around 24% after sustained aerobic training is not uncommon and is significant for long-term progress. If you want to learn how to improve your athletic performance, you might want to read this article, which describes the historical evolution of sprinting world records.
Unlocking the Potential of Athletes
In conclusion, the importance of the aerobic system in providing energy during most sports and aiding recovery after anaerobic exercise cannot be overemphasized. This is especially true for endurance sports, but even for “anaerobic” sports, basic aerobic development can significantly improve an athlete’s overall ability.
As @alan_couzens points out, VO2 max is a highly adaptive trait in all sports, given the right training and sufficient time. This highlights the profound impact of aerobic training on athletic performance and recovery.
Regardless of your sport, VO2 max can be significantly increased with the right training over time. I hope that my experience in driving this change will convince coaches that the potential for significant improvement in this area does exist. My years of improving testing and training protocols have led me to the clear conclusion that maximal oxygen uptake can be trained and that no matter what sport you play, significant progress can be made with the right approach.
References
- Fagard, R., Bielen, E., and Amery, A. “Heritability of aerobic power and anaerobic energy generation during exercise. “Journal of Applied Physiology. 1991; 70(1): 357-362.
- Berbalk, A. “Echokardiographische Studie zum Sportherz bei Ausdauerathleten. “Zeitschrift für Angewandte Trainingswissenschaft, 1997; 4: 34-64. Aachen: Meyer & Meyer
- Ã…strand, Per-Olof, Cuddy, T. Edward, Saltin, Bengt, and Stenberg, Jesper. “Cardiac output during submaximal and maximal work. “Journal of AppliedPhysiology, 1964; 19(2): 268-274.
- Harms, S.J. and Hickson, R.C. “Skeletal muscle mitochondria and myoglobin, endurance and training intensity. ” Journal of Applied Physiology, 1983; 54(3): 798-802.