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Is VO2max Genetic? How Trainable FTP and VO2max Really Are

By James Vickers and Lyra, WattPlan's AI research voice··14 min read

The WattPlan Podcast · Episode 13 · 9 min

Is VO2max genetic, and how much can you train it?

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James asks, Lyra answers from the studies. All episodes · RSS

Next episodes: How do you actually raise your FTP? · How do you plan a season so you peak on the day? · How long does heat training take for cycling?

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James. This is the WattPlan Podcast, and I'm James. My week's a juggle of family, work, building WattPlan and the occasional podium, with more sports science squeezed into the gaps than anyone needs. Today's the one every rider who's been dropped on a climb has wondered about. Is VO2max just genetic, and how much can training really move it, or my FTP? Lyra, our AI research voice, has read the studies, and they're all linked in the show notes.

Lyra. Partly, yes. Both where you start and how much you respond to training run in families. But FTP leans heavily on how much of that ceiling you can actually use, and training changes that a lot. So your genes shape the range. Your training decides where you land in it.

James. Okay, start with the scary bit. How much is genetic?

Lyra. The big study here is the HERITAGE Family Study. Bouchard and colleagues, 1999, in the Journal of Applied Physiology. They took nearly five hundred sedentary adults from 98 families, all white, and trained every one of them on the same programme for twenty weeks. [5]

James. Same programme, so presumably everyone got roughly the same out of it.

Lyra. Nowhere near. On average VO2max, the most oxygen you can use, went up by about 400 millilitres a minute. But some people gained little or nothing, and others more than a litre a minute. And the responses clustered in families. There was far more variation between families than within them.

James. So how much of that clustering is actually genes?

Lyra. Their best model put the heritability of the response at up to 47 percent. The authors concluded that trainability is highly familial and includes a significant genetic component.

James. But families share kitchens and habits as well as genes. Isn't some of that just how you were brought up?

Lyra. Yes, and that's why the authors call 47 percent a maximal estimate. Family studies can't fully separate genes from a shared life. So the honest reading is that a real chunk of trainability runs in families, and nobody can tell you exactly how much is DNA.

James. Right, so there really are non-responders. Some of us just don't get fitter, surely?

Lyra. That's the framing I'd push back on, and the second study is why. Montero and Lundby, 2017, in The Journal of Physiology. Nearly eighty healthy adults trained for six weeks, in groups doing anywhere from one to five one-hour sessions a week. With one session a week, more than two thirds didn't improve their maximal power in a ramp test. With four or five, every single one did. [16]

James. And the ones who didn't improve? Were they just written off?

Lyra. They did another six weeks with two extra sessions a week, and every one of them improved. The authors put most of the gain down to more haemoglobin, the protein that carries oxygen in the blood. So in that study, not responding mostly meant not enough training for that person yet. Healthy adults rather than trained cyclists, though, and six week blocks.

James. So genes decide how much you get from a given amount of training, but nearly everyone responds if there's enough of it.

Lyra. For those two studies, yes, with a caution. Both trained people who were starting from untrained, over weeks, not years. Nobody has followed amateur cyclists for a decade to see how far apart their genes keep them. And nothing here can tell you your own ceiling.

James. Which is oddly cheering if you're new to this.

Lyra. It is. If you're new to structured training, you're in a good place. HERITAGE and the six week study were both on people starting out, and the average gains were real. WattPlan starts a beginner on one harder ride a week, sweet spot, with everything else easy. Your job is turning up, because Montero's result says the amount of training you actually do is what moved the stubborn ones.

James. But here's my real worry. If my VO2max is only average, am I capped?

Lyra. Not by that alone, and the third study is my favourite on this. Coyle, Coggan and colleagues, 1988, in the Journal of Applied Physiology. Fourteen competitive cyclists, men, all with almost the same VO2max. In half of them, lactate threshold came at about two thirds of VO2max. In the other half it came at over four fifths. [7]

James. And that difference showed up on the bike?

Lyra. Very much. Riding at the same hard effort, the second group lasted more than twice as long, about an hour against under half an hour. And over nine tenths of that difference went with two things, where the threshold sat as a share of VO2max, and how many capillaries fed the muscle.

James. Same engine, more than twice the endurance. That's wild.

Lyra. That share is called fractional utilisation, how much of your ceiling you can use for a long effort. It's a big part of what FTP measures, and it's trainable. Picture two riders with the same VO2max. One can hold about 55 percent of it for an hour, the other about 85. The second has over half as much again to ride with, from the same engine.

James. Which sounds like the whole game if you race. Is that really trainable, or is it another thing you're born with?

Lyra. If you race, that's the encouragement in Coyle's result. Two riders with the same VO2max can be a long way apart at threshold, and that gap is trained. The sweet spot, threshold and long endurance riding in your plan are what move it. And the things that settle a lot of amateur races, pacing, positioning, fuelling, aren't in your genes at all.

James. So how does WattPlan go after both, the ceiling and the share?

Lyra. In the base phase, the harder days are sweet spot. In build and peak, most riders with two hard days get a VO2max session alongside sweet spot or threshold work for the share you can use. Everything else is endurance riding, which is what builds the capillaries.

James. Only one VO2max session a week, though? If the ceiling's what holds me back, I'd want three.

Lyra. One at most, and on purpose. Hard days need easy days around them, and the plan spends its harder sessions across both the ceiling and threshold, rather than stacking VO2max work. For a rider whose ceiling is average, that's the point. The share you can use is the part that keeps moving.

James. And how would I even see it moving? I train with power, so I'd want a number.

Lyra. With a power meter, a plan without an event finishes on an FTP test, so ride it and your zones keep up with you. If sessions keep feeling easier than planned with power on target, the Coach can suggest testing sooner. If heart rate is your only number, the plan finishes on the 30-Minute Heart-Rate Test instead. Either way, judge progress over a whole plan, not one ride.

James. Where does the evidence run out?

Lyra. Quite early. HERITAGE was sedentary white adults, Montero measured six week blocks, and Coyle's fourteen were men. None of them followed trained amateurs over years, and none can predict one rider's ceiling from their family or their genes.

James. Then what do I do with all this on Monday?

Lyra. Stop asking whether you're a responder. One block can't tell you, and the best evidence says the dose matters more. Ride your plan for its whole length, recovery weeks included, and ride the test at the end. Then judge yourself on your Fitness and your FTP over months, not on one bad session.

James. No more wondering if I got the wrong genes. Whole plan, easy weeks and all, then the test, and I judge it in months, not by one grim Tuesday.

Lyra. You can't choose your parents. You can choose to turn up for twelve weeks, and then the twelve after that.

Lyra. The full article and every study we mentioned are on the WattPlan blog, linked in the show notes. And if you've enjoyed this, follow the WattPlan Podcast wherever you're listening, so you don't miss the next one.

James. And if you want a plan built around the time you've actually got, get WattPlan on the App Store or Google Play. Thanks for listening.

Voices produced with ElevenLabs. James's voice is a clone of his own, Lyra is an AI voice, and James reviews every episode.

Every cyclist who has ever been dropped on a climb or outsprinted in the final kilometre has asked the same question. Is this about talent, or am I just not training hard enough?

The answer, according to decades of exercise physiology research, is more nuanced than either extreme. Genetics matter. But they matter less than most people think, and far less than how you train. The two metrics at the heart of this debate are VO2max (your aerobic ceiling) and FTP (your sustainable power at threshold). Understanding what each one is, how trainable each one is, and how they relate to each other is essential for any cyclist serious about improving.

This article examines the science. It draws on landmark studies, professional cycling data, and practical coaching insight to answer the question that matters most, which is whether a less genetically gifted rider can still become a competitive cyclist.

What Are FTP and VO2max?

VO2max, the Aerobic Ceiling

VO2max is the maximum rate at which your body can consume oxygen during exercise. It is measured in millilitres of oxygen per kilogram of body weight per minute (ml/kg/min). The higher your VO2max, the more oxygen your muscles can use to produce energy aerobically.

VO2max is determined by three factors.

Elite male cyclists typically have VO2max values between 70 and 85 ml/kg/min. Elite women range from 60 to 75 ml/kg/min. Untrained adults sit around 35-45 ml/kg/min (Bassett & Howley, 2000).

Think of VO2max as the size of your engine. A larger engine has more potential, but potential alone does not win races.

FTP, the Sustainable Output

Functional Threshold Power is the highest average power you can sustain for approximately one hour. In physiological terms, it closely approximates the power output at your maximal lactate steady state (MLSS), the intensity above which lactate accumulates faster than your body can clear it.

FTP is typically expressed in watts or watts per kilogram (W/kg). It represents the boundary between sustainable and unsustainable effort. Everything below your FTP is metabolically manageable over time. Everything above it has a ticking clock.

Where VO2max is the size of the engine, FTP is how much of that engine you can actually use for sustained work. This distinction is critical, because it is entirely possible, and common, for two cyclists with the same VO2max to have very different FTPs.

How Much of VO2max Is Genetic?

The HERITAGE Family Study

The most comprehensive investigation into the genetics of aerobic fitness is the HERITAGE Family Study (Bouchard et al., 1999), which followed 481 sedentary adults through a standardised 20-week endurance training programme. The findings were striking.

This created the concept of "high responders" and "low responders", people whose bodies adapt more or less readily to endurance training.

Twin Studies

Research on identical and fraternal twins has reinforced the HERITAGE findings. A study by Prud'homme et al. (1984) trained ten pairs of identical twins for 20 weeks and found that gains ranged from about 0% to 41%, yet twins in the same pair responded very similarly, pointing to a strong genetic influence on trainability. Subsequent work by Bouchard et al. (1986) estimated that genetic factors account for 40-60% of the variance in VO2max.

What Genetics Actually Control

The genetic influence on VO2max operates through several mechanisms.

However, and this is the critical point, genetics set the range, not the outcome. A person with a genetically lower ceiling can still, through training, reach a VO2max higher than an untrained person with superior genetic potential.

How Trainable Is VO2max?

The Evidence

VO2max is trainable, but with diminishing returns. The typical training response in previously sedentary individuals is a 15-25% improvement over the first 3-6 months of structured endurance training (Bacon et al., 2013). Some individuals respond even more dramatically. The HERITAGE study recorded improvements up to 40%.

However, this improvement curve flattens as fitness increases. Well-trained riders who have been training consistently for several years may see only 3-5% further improvement in VO2max from additional training (Jones & Carter, 2000). At the elite level, VO2max tends to plateau, and further performance improvements come from other adaptations.

The Responder Problem

Not everyone responds equally. Around one in five people show little VO2max change on a standard programme, although when training volume was increased every one of them improved (Montero & Lundby, 2017).

What the headline rarely mentions is that low VO2max responders are not necessarily low performance responders. A cyclist may see little change in VO2max but substantial improvement in lactate threshold, efficiency, and sustainable power. Performance is not VO2max alone.

What Moves VO2max

The most effective training for improving VO2max is high-intensity interval training at 90-100% of VO2max, typically 3-8 minute intervals at 106-120% of FTP (Laursen & Jenkins, 2002). These sessions drive adaptations in the following.

One to two VO2max sessions per week during a build phase is the established recommendation. More than this tends to add fatigue faster than it adds fitness.

How Trainable Is FTP?

Here is where the story becomes much more encouraging for the genetically average cyclist. FTP is highly trainable, far more so than VO2max, because it depends on adaptations that respond reliably to consistent, structured training.

The Physiology Behind FTP Trainability

FTP is governed by three trainable factors.

1. Fractional Utilisation

This is the percentage of VO2max you can sustain at threshold. An untrained individual might sustain only 50-60% of their VO2max. A well-trained cyclist can sustain 80-90% (Coyle et al., 1988, and Joyner & Coyle, 2008). This is an enormous performance gain that requires no change in VO2max.

Consider two cyclists, both with a VO2max of 60 ml/kg/min.

CyclistVO2maxFractional UtilisationEffective Aerobic Power
Untrained6055%33 ml/kg/min
Trained6085%51 ml/kg/min

The trained cyclist produces 55% more sustainable aerobic power from the same VO2max. This is the single largest source of performance improvement available to most cyclists.

2. Lactate Kinetics

Training improves your body's ability to produce, shuttle, and clear lactate. Type I muscle fibres develop greater lactate oxidation capacity. The MCT1 and MCT4 lactate transport proteins increase in density. The net result is that you can sustain higher power outputs before lactate accumulates to the point of failure (Juel, 2008).

These adaptations respond strongly to Sweet Spot training (88-94% FTP), threshold intervals (95-105% FTP), and sustained endurance work.

3. Gross Mechanical Efficiency

Efficiency is how many watts you produce per litre of oxygen consumed. Better efficiency means more power from the same aerobic input. While baseline efficiency has a genetic component, it tends to improve with years of consistent cycling, particularly high-volume endurance riding (Coyle et al., 1992), although how much, and how long it keeps improving, varies widely between riders.

FTP Improvement Potential

A rider moving from untrained to well-trained can see large gains in FTP over the first few years of structured training, and experienced riders can keep improving more slowly by addressing limiters and building consistency.

This stands in sharp contrast to VO2max, where gains of 3-5% per year are exceptional for trained riders.

The Relationship Between FTP and VO2max

FTP and VO2max are linked but not locked. Understanding their relationship explains why training history matters more than genetic starting point.

FTP as a Percentage of VO2max

In most trained cyclists, FTP sits at 72-82% of the power output at VO2max (often called MAP or maximal aerobic power). In professional cyclists, threshold can sit at 85-90% of VO2max.

This means there are two distinct pathways to a higher FTP.

  1. Raise VO2max (raise the ceiling) through VO2max intervals and high-intensity work
  2. Raise fractional utilisation (move FTP closer to the ceiling) through threshold, Sweet Spot, and endurance training

A cyclist who has plateaued on VO2max can continue improving FTP by pushing fractional utilisation higher. In a six-year case study of one Grand Tour rider, record power from five minutes to four hours kept rising between ages 18 and 23 as training load grew (Pinot & Grappe, 2015).

The Transfer Effect

Training one metric often improves the other, to a degree.

The practical implication is that a well-designed training plan addresses both. Pure threshold work without any VO2max training eventually hits a ceiling. Pure VO2max training without threshold and endurance work leaves sustainable power undeveloped.

Can Less Gifted Riders Still Compete?

If genetics determined everything, the same riders would win every race from age 16 onwards. They do not. Here is why.

1. Fractional Utilisation Is the Great Equaliser

Two riders line up for a 40km time trial.

RiderVO2maxFractional Util.FTP (W/kg)
Rider A (gifted)7572%4.2
Rider B (average)6288%4.2

Same FTP. Same race performance. Rider B has a VO2max 17% lower than Rider A but compensates entirely through superior fractional utilisation, an adaptation earned through years of consistent training.

This is not a theoretical scenario. Research on professional cyclists has shown that VO2max alone is a poor predictor of time trial performance within a group of trained riders. Lactate threshold power and efficiency are significantly better predictors (Coyle et al., 1991, and Lucia et al., 2002).

2. Durability, the Long-Ride Advantage

Races are not won in laboratories. They are won after 4, 5, 6 hours on the road, when fatigue has stripped away the fresh-legs advantages. Durability, the ability to sustain power output over long durations, appears to respond well to training, though research on how best to build it is still young (Maunder et al., 2021).

Riders who build high training volumes develop superior fat oxidation, glycogen sparing, and resistance to cardiac drift. These adaptations allow them to maintain a higher percentage of their FTP deep into a race, even if their peak numbers are modest.

In a race longer than three hours, a rider with excellent durability can close much of the gap to a rider with a higher FTP who fades.

3. Efficiency Compounds Over Years

Efficiency tends to improve with years of riding, although how much, and how long it keeps improving, varies widely between riders.

Even so, over a one-hour effort, 3% better efficiency at the same oxygen consumption translates to roughly 8-12 watts. Over a five-hour race, the cumulative advantage is substantial.

4. Body Composition Is Controllable

Watts per kilogram determines climbing speed. While VO2max per kilogram has a genetic component, body composition is largely within a rider's control. A rider who optimises body composition through nutrition and training can improve their W/kg without changing absolute power.

5. Tactical and Mental Factors

Pacing, positioning, race craft, nutrition execution, heat acclimatisation and altitude preparation are not genetic. They are skills and strategies refined through experience and deliberate practice. In amateur racing, these factors routinely determine results more than raw physiological talent.

Training Strategies That Maximise What You Have

If genetics set the boundaries, training determines where within those boundaries you land. Here are the evidence-based strategies that extract the most from your physiology.

Build a Large Aerobic Base

High-volume Zone 2 training (56-75% FTP) develops mitochondrial density, capillary networks, fat oxidation, and cardiac adaptations. These are the foundational adaptations that improve both VO2max and FTP. Seiler's research on elite endurance competitors consistently shows that approximately 80% of training should be at low intensity (Seiler, 2010).

This does not mean riding slowly is enough. It means the aerobic base is what makes high-intensity work productive.

Periodise Your Intensity

The remaining 15-20% of training should be structured in blocks.

Periodisation ensures you develop all energy systems without accumulating excessive fatigue. The polarised training model (most training easy, some very hard, little in between) has produced slightly larger VO2max gains than other approaches in pooled trials, mainly in short blocks and highly trained riders, with no clear difference in time-trial performance (Silva Oliveira et al., 2024). Recreational riders may do as well or better with a pyramidal mix (Rosenblat et al., 2025).

Be Consistent Over Years

Perhaps the most underappreciated factor in cycling performance is training age, the number of years of consistent, structured training. Many of the adaptations that separate competitive from recreational cyclists develop over 5-10 years.

A genetically average cyclist with 8 years of structured training will outperform a genetically gifted cyclist with 2 years of training in nearly every competitive scenario.

Address Your Limiters

If your FTP has plateaued but your VO2max is low relative to your FTP, you need VO2max work, because your ceiling is the limiter. If your VO2max is adequate but your FTP sits at only 70% of MAP, you need more threshold and Sweet Spot work, because your fractional utilisation is the limiter.

The power-duration curve reveals these relationships. A cyclist with strong 5-minute power but weak 20-minute power has untapped threshold potential. A cyclist whose 20-minute power is already close to their 5-minute power needs to raise the ceiling.

Recover Properly

Adaptation occurs during recovery, not during training. Sleep, nutrition, stress management, and programmed rest weeks are not optional extras. They are where the training response is realised. Insufficient recovery is the most common reason training fails to translate into performance gains, regardless of genetics.

The Bottom Line

VO2max has a significant genetic component, with up to roughly half of the variation between individuals inherited. But VO2max is still trainable by 15-25% in untrained individuals, and it is only one factor in cycling performance.

FTP is far more trainable than VO2max. It responds to structured training through improved fractional utilisation, lactate kinetics, and mechanical efficiency. A cyclist with a modest VO2max who trains intelligently for years can achieve the same FTP as a genetically gifted cyclist who trains poorly.

The evidence points one way. Genetics determine potential, but training determines performance. The gap between a genetically average cyclist and a genetically gifted one narrows with every year of consistent, structured work. In amateur cycling, where the genetic spread is wide and training quality varies enormously, that gap can close a long way.

The riders who reach their potential are not always the ones with the highest VO2max. They are the ones who train consistently, recover properly, address their limiters, and commit to the process over years. The engine matters. But how you build, tune, and run it matters more.

Sources

Continue Reading

Training

How to Increase FTP, What the Training Trials Measured

How to increase FTP, from the trials. Two interval sessions a week, 4 x 8 minutes beat 4 x 4 and 4 x 16 in Seiler's study, plus easy riding and a recovery week.
Analytics

How to Read Your Cycling Power Curve

How to read your cycling power curve. What your best power at 5 seconds, 1, 5 and 20 minutes says about your strengths, limiters and training.

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