Can Grand Tours Suffocate You? A New Study Looks at Respiratory Function in Cycling’s Hardest Races

Suck It Up, Buttercup.

TOOLBOX: Riding cycling’s Grand Tours is about the hardest athletic gig that you can find. Over the years, scientists have tracked the power demands and its impact on different physiological systems. A new study explores how these three-week races affect respiratory function and symptoms.

There is no doubt that riding a Grand Tour, let alone being competitive or winning it, is one of the most impressive athletic feats we could dream up. Besides the sheer power demands of each individual stage, simply being able to eat and assimilate enough calories is an enormous challenge that would defeat most adults outside of July 4 Coney Island hot dog eating contestants.

Of course, being an outdoor sport, athletes have no control over the environment, ranging from near freezing in the high mountains to the blast oven that is the Vuelta. Then there’s the challenges of repeating such efforts for 21 stages over 23 days and its incredible requirements on recovery capacity.

As an added cherry on top of this pain sundae, there’s the logistical challenges of moving every day, along with often sub-standard hotels, mixed in with the internal and external pressure involved in performing under the biggest spotlight within the sport.

Take a Calming Breath?
Fans of mindfulness and meditation are taught to focus on the breath. But are there effects from riding GTs on the respiratory system? While recreational cycling by itself may be a healthy endeavour, pro riders are often encased in a cocoon of pollution from the dozens and dozens of surrounding team/race cars and motorcycles. Individual riders may also have various respiratory conditions such as allergies or exercise-induced bronchoconstriction (EIB) through to asthma.

The intensity of exercise means ventilation can easily rise to 100-150 L/min, such that breathing switches from predominately through both the nose and mouth to almost completely just through the mouth, meaning less filtering of particles and also that pollutants can reach deeper into the respiratory tract.

Breathe In
A new “In Press” article in the European Journal of Applied Physiology from a UK research group tracked pro riders during the 2018/2019 season, specifically La Vuelta and Le Tour, to monitor for the first time the respiratory impact of these events (Allen et al. 2021). Here are the study details:

Eleven cyclists were initially recruited during the 2018 and 2019 Vueltas and Tours. No firm detail is provided, but it seems like it was the 2018 Vuelta and 2019 Tour.

No info is provided on whether there were any repeat customers in this cohort (i.e., the same rider tested during different GTs), nor was there any info on their racing history or roles (e.g., whether they were leaders, sprinters, domestiques, etc. Riders were fairly experienced, with mean age of 30±3 years, so presumably they have had ridden GTs previously rather than being neo-pros.

5 riders were diagnosed previously with EIB. All 5 used some form of pharmacological treatments regularly and throughout the GT.

Common respiratory measures were taken at Pre-GT (48 h prior to start), Mid-GT (afternoon of the 2nd rest day about 17 days in), and Late-GT (morning of the final stage). Measures included Forced Vital Capacity (FVC, maximal inspiration followed by maximal expiration), Forced Expiratory Volume (FEV1, how much air can be expired within 1 second).

Airway inflammation was measured through measuring fractional exhaled nitric oxide (FeNO), with higher values representing greater inflammation.

Inspiratory force was tested Pre-GT and Late-GT by measuring Sniff-nasal inspiratory pressure (SNIP) , where one nostril is plugged and you inspire as intensely as possible through the other nostril.

Subjective ratings of symptoms were also measured of cough; throat discomfort; voice changes; breathlessness; and difficulty swallowing, eating or drinking.

Breathe Out
Such a study would be meaningless to do in a lab, as a GT’s unique circumstances are impossible to replicate. Of course, following a GT creates its own logistical headaches, limiting the amount and complexity of testing that can be done. What measures were done, though, were done well and according to clinical standards.

Two cyclists abandoned the race, so total analysis was done on nine riders (4 from Vuelta, 5 from Tour).

7/9 reported respiratory symptoms, with a fairly random frequency except for voice changes with a cough in 6 of these 7 cyclists. Generally, symptoms got worse over the course of the GT.

All riders had normal lung function at Pre-GT, thought 5 had a high FeNO at Pre-GT.

Both FVC and FEV1 decreased over time, with 8 cyclists demonstrating a FEV1 drop of >200 mL and 6 showing a FVC drop of >200 mL.

5 cyclists performed the SNIP test of respiratory muscle strength, with no changes observed over time.

GT and the Lungs
Being the first study of its kind and with a limited sample, it is hard to draw overall conclusions from this single study. However, it is a good start on this field and points the way towards future research.

There is a continuing debate within the exercise physiology field whether, for most individuals not suffering from an overt disease like asthma, the respiratory system is significantly overbuilt compared to the demands placed on it even during heavy exercise.

What isn’t up for debate is that breathing is such a primal demand and urge that, when restricted, it is not just physically uncomfortable but can cause severe psychological distress. Given what we now know about the strong interplay between psychology and physiology, the discomfort from breathing impairments can force the brain to slow the body down to maintain the body’s safety.

Therefore, for these highly trained racers at the edge of their physical capacities, it is possible that the slight impairment in respiratory function is enough to contribute to the lower power outputs commonly seen during the later stages of GTs.

What also has not been studied are the respiratory function of these extreme athletes over seasons and in the years and decades of their overall life, to see whether these impairments compound over time.

Ride fast and have fun!


Allen H, Price OJ, Greenwell J, Hull JH (2021) Respiratory impact of a grand tour: insight from professional cycling. Eur J Appl Physiol.


Grand Tourslatest newsNow on pezrespiratory trainingScienceToolbox