Extraordinary hearts and lungs: the things that set elite cyclists apart

By Martin LaSalle Aug 3rd, 2026

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In 5 seconds What separates the world’s top cyclists from weekend warriors? UdeM’s Daniel Curnier explains the science behind their superhuman edge.

An active cyclist rides about 10,000 kilometers a year, while a elite athlete covers between 25,000 and 35,000 kilometers.
Photo : Getty

Roughly 1,000 elite cyclists will compete in the UCI Road World Championships, held this year in Montreal from September 20 to 27. How do these athletes differ physically from a well-trained amateur cyclist—or from someone watching them on TV from the couch?

One way of answering the question is to look at how much oxygen the athlete consumes when exercising.

“An elite athlete can take in up to four times as much oxygen as a sedentary person,” said Daniel Curnier, a professor in Université de Montréal's School of Kinesiology and Physical Activity Sciences and a specialist in exercise physiology.

“That's a difference we basically see when there's physical exertion, not when they’re at rest.”

The difference is captured by a metric called VO₂ max (maximum oxygen consumption). At rest, the value varies little from person to person, but under maximal exertion, it widens dramatically. A sedentary person needs about 25 to 30 millilitres of oxygen per kilogram of body weight per minute, a competitive amateur cyclist 50 to 60, and an elite cyclist 80 to 90.

Curnier offered a caveat, however: “There isn’t actually a huge time gap between the best amateur cyclists and the top pros,” he said. On the Tour de France’s annual amateur stage, for instance, amateurs clock times that are not so far from the pros. But that is mainly because of racing tactics.

“In an amateur peloton, everyone works together and rides flat out from start to finish, whereas the pros pace themselves until the final kilometres,” Curnier explained. “Take a single climb, with no tactical considerations, and the gap becomes much more pronounced.”

Daniel Curnier, professor at the School of Kinesiology and Physical Activity Sciences at Université de Montréal
Photo : Amélie Philibert, Université de Montréal

The heart: an engine with limits

The second major divide between amateur and elite cyclists is cardiac output, the volume of blood pumped by the heart in one minute.

At maximum exertion, a trained amateur pushes 20 to 25 litres per minute. An elite rider, by contrast, can reach up to 45 litres, thanks to a heart that has thickened and enlarged through years of intense training.

However, that hypertrophy comes at a cost. “These athletes have hearts so powerful that, at maximum effort, oxygen intake can’t keep up with the heart rate,” Curnier explained. “So blood oxygen levels drop. It’s called ‘exercise-induced hypoxemia.’”

Curnier believes this ceiling, not just sheer strength, is what sets the champions apart.

Resting heart rate tells a similar story: around 70 beats per minute for the average person, often below 35 for champions.

Pedalling harder and longer

Beyond heart and lungs, the mechanical efficiency of pedalling is also an important factor in performance.

An amateur cyclist typically produces 2 to 3 watts per kilogram of body weight; a competitive cyclist who reaches 4 W/kg is already considered high-performing, and 5 W/kg “opens the door to the top teams,” Curnier said. The superstars, such as Tadej Pogačar, can sustain 6 to 7 W/kg for 30 to 40 minutes.

The riders' power output hinges largely on their lactate threshold, the exercise intensity at which blood lactate rises sharply. (Functional threshold power, or FTP, the power an athlete can sustain for an hour, is increasingly used as a proxy for lactate threshold.) At the same intensity, elite athletes clear lactate faster, which means they can pedal longer at higher intensity.

One final factor sets champions apart: their ability to withstand the wear and tear of sustained effort, like an engine that refuses to quit. Curnier calls this “durability.” If a champion and a well-trained amateur both ride at the same percentage of their respective VO₂ max, the champion will maintain efficient pedalling and high power far longer, while the amateur’s performance fades more quickly.

Astounding training volumes

The pro athlete’s physiological superiority is built up through training. Riders on the UCI ProTour and Continental teams train for more than 20 hours a week, sometimes 30 to 35 hours.

An active cyclist covers about 10,000 kilometres a year, while a high-level athlete will log 25,000 to 35,000, largely at low intensity.

“To illustrate the point, when Pogačar does a ‘light’ training session, he’s still putting out more than 300 watts, which is close to the maximum of many riders,” said Curnier, who is currently working with Cycling Canada to prepare athletes for the Los Angeles Olympics.

For an untrained amateur, maximum output generally falls between 100 and 150 watts.

Risks and rewards

High-level training is not without hazards: falls, infections from a taxed immune system, post-race inflammation and a higher prevalence of heart-rhythm disorders associated with hypertrophy.

Yet Curnier believes the long-term benefits far outweigh the risks. He points to a study that tracked all participants in the Tour de France from 1940 to 2010 and compared their mortality rates with an age-matched control group.

“They found that the athletes had a significantly lower mortality rate across all periods studied, including when doping was more widespread among the athletes,” Curnier said.

Comparison of key physiological indicators

Indicator	Sedentary individual	Trained amateur cyclist	Elite cyclist
VO2 max (mL/kg/min)	25 to 30	50 to 60	80 to 90
Maximum cardiac output (L/min)	—	20 to 25	Up to 45
Resting heart rate (bpm)	~70	~60	~35
Power (watts/kg)	—	2 to 3	6 to 7
Annual training volume (km)	—	~10,000	25,000 to 35,000