You obsess over your power numbers. You track your weight to the decimal. You have a recovery protocol, a nutrition plan, and a periodised training calendar. But the organ responsible for delivering oxygen to every single watt you produce — the one organ you cannot train harder, cannot upgrade, and cannot replace — gets almost no attention.
Your lungs.
For most cyclists, respiratory health only enters the conversation when something goes wrong: a chest infection that wipes out a month of training, a persistent cough that appears after threshold intervals, or a gradual decline in performance that no amount of extra volume seems to fix. By the time the symptom surfaces, the problem has usually been building for months or years.
This is the guide to looking after the system that everything else depends on. Air quality, cold air, pollution, exercise-induced bronchoconstriction, and the respiratory training that can add measurable watts for less than $30.
What cycling does to your respiratory system
At rest, you breathe approximately 12-20 times per minute and move about 6-8 litres of air. During a hard effort on the bike, your respiratory rate climbs to 40-60 breaths per minute and you move 100-150 litres of air. At VO2max, ventilation can exceed 180 litres per minute in trained cyclists.
This 10-20x increase in ventilation is the fundamental issue. Whatever is in the air — oxygen, nitrogen, particulate matter, nitrogen dioxide, ozone, pollen, diesel exhaust — you are inhaling 10-20 times more of it per hour when riding than when walking the same route. The filtration capacity of your nose is overwhelmed at high ventilation rates, which is why you switch to mouth breathing above about 70 per cent of VO2max. Mouth breathing bypasses the nasal turbinates — the structures that warm, humidify, and filter incoming air.
The result: during a two-hour training ride on an urban road, your lungs process roughly the same volume of air that a sedentary person processes in an entire day. If that air contains pollutants, your exposure is dramatically amplified compared to someone sitting in a car on the same road.
This does not mean cycling is bad for you. The cardiovascular benefits of cycling vastly outweigh the respiratory costs of pollution in most contexts. Studies consistently show that regular cyclists have better lung function than sedentary individuals, even when cycling in urban environments. But the margin of benefit shrinks as pollution exposure increases, and there are practical steps you can take to shift that balance further in your favour.
Air quality: the variable you are ignoring
Air quality is invisible, which is why it gets ignored. You can feel heat. You can see rain. You cannot see particulate matter. But its effects on your respiratory system — and your performance — are measurable.
The three pollutants most relevant to cyclists:
Particulate matter (PM2.5 and PM10). Tiny particles of soot, dust, and organic matter suspended in the air. PM2.5 — particles smaller than 2.5 micrometres — penetrate deep into the lungs, past the bronchi and into the alveoli where gas exchange happens. Long-term exposure is associated with reduced lung function, increased airway inflammation, and higher rates of respiratory disease. Short-term exposure during exercise causes measurable reductions in FEV1 (the volume of air you can forcefully exhale in one second) that persist for 12-24 hours after the ride.
Nitrogen dioxide (NO2). Produced primarily by vehicle exhaust. Concentrations are highest within 50 metres of busy roads and during rush hour. NO2 irritates the airway lining and increases susceptibility to respiratory infections. A study of London cyclists found that riding on busy roads during rush hour increased NO2 exposure by 2-3 times compared to riding on quiet residential streets just 200 metres away.
Ground-level ozone. Formed when sunlight reacts with vehicle emissions. Ozone is paradoxically higher on warm, sunny days — exactly the days when cyclists are most likely to be out. It causes airway inflammation, reduces lung function, and triggers coughing and chest tightness, particularly during prolonged exercise.
Practical pollution avoidance
You do not need an air quality science degree. You need three habits:
Check the forecast. The Air Quality Index (AQI) is available on most weather apps and government environment websites. An AQI below 50 is good. Between 51-100 is moderate — acceptable for training. Above 100, consider training indoors or shifting your ride to a time when the index drops. Above 150, train indoors.
Route selection. Ride on quiet roads, separated cycle paths, canal towpaths, and park roads when available. The difference in pollutant concentration between a busy A-road and a residential street 200 metres away is significant enough to affect your breathing during a two-hour ride. This is not hypothetical — London School of Hygiene research measured the difference and found that cyclists on quieter routes inhaled 30-50 per cent less NO2 per ride.
Time of day. Urban air quality is worst during rush hour (7-9am and 4-7pm) when traffic volume peaks. It improves substantially by mid-morning as traffic disperses and the atmosphere mixes. If you have flexibility in when you ride, starting at 10am instead of 7:30am meaningfully reduces your pollution exposure. Weekend mornings — less traffic, lower emissions — are even better.
Exercise-induced bronchoconstriction: the diagnosis most cyclists miss
Exercise-induced bronchoconstriction (EIB) is the narrowing of the airways during or after exercise. It is not the same as asthma, though the two overlap. You can have EIB without having asthma, and many endurance athletes develop it through years of high-ventilation training.
The prevalence numbers are striking. Studies of elite endurance athletes estimate that 10-50 per cent have some degree of EIB, depending on the sport and testing methodology. Swimmers, cross-country skiers, and cyclists — athletes who sustain very high ventilation rates for prolonged periods — have the highest rates.
The mechanism: during intense exercise, the rapid flow of air through the bronchi dries and cools the airway lining. This triggers an inflammatory response, causing the smooth muscle around the bronchi to constrict. The narrowing reduces airflow, which the athlete experiences as chest tightness, a cough, wheezing, or a feeling that they "cannot get enough air" despite breathing as hard as possible.
The problem is that these symptoms mimic poor fitness. A rider who struggles to sustain VO2max intervals, who coughs for 20 minutes after every hard session, or who wheezes on cold descents is more likely to conclude they need to train harder than to consider a respiratory condition. Coaches miss it too — the rider's power numbers look fine at lower intensities, and the limitation only appears at the high end.
Do you have it?
Consider the possibility if you recognise two or more of these:
- A dry, persistent cough that starts 5-10 minutes after finishing a hard effort and lasts 15-30 minutes
- Chest tightness during efforts above threshold that feels different from muscular fatigue
- Wheezing during or immediately after riding in cold air
- A noticeable decline in high-intensity performance that does not correlate with training load or recovery
- A feeling of "breathing through a narrow straw" during VO2max efforts, even when your cardiovascular system seems capable of more
Getting diagnosed
Standard spirometry — the test where you blow into a tube at a doctor's surgery — misses EIB in up to half of cases. The airways are not constricted at rest; the problem only manifests during exercise. You need a provocation test.
The gold standard is the eucapnic voluntary hyperventilation (EVH) test. You breathe dry air at high ventilation rates for 6 minutes, mimicking the conditions of hard exercise. Spirometry is then performed at intervals afterward to detect airway narrowing. A 10 per cent or greater drop in FEV1 confirms EIB.
Alternatively, an exercise challenge test — performing spirometry before and after a controlled bout of high-intensity exercise — can detect EIB, though it is less sensitive than the EVH test.
If diagnosed, the treatment is typically a short-acting bronchodilator (salbutamol/Ventolin) taken 15-20 minutes before exercise. This is permitted under WADA anti-doping rules without a therapeutic use exemption. For more persistent cases, an inhaled corticosteroid provides ongoing airway inflammation control.
The point is not to diagnose yourself. The point is to recognise that the symptoms exist and that investigation is available. Many endurance athletes live with undiagnosed EIB for years, working harder to compensate for airways that are not fully open, when a $10 inhaler would resolve the issue.
Cold air: the slow damage nobody warns you about
Cold air is dry air. When air temperature drops below about 5 degrees Celsius, the moisture content falls sharply. Breathing cold, dry air at the high ventilation rates cycling demands strips moisture from the airway lining, which triggers bronchospasm in susceptible individuals and, over time, contributes to airway epithelial damage.
Cross-country skiing research — the closest analogue to cycling in terms of cold air exposure and sustained ventilation — has documented airway remodelling in elite winter sport athletes. The bronchial walls thicken, the mucous glands enlarge, and the airways become hyper-responsive to irritants. This is not acute injury from one cold ride. It is cumulative damage from thousands of hours of cold, dry air exposure over a career.
For the masters cyclist training through winter in the UK, Ireland, or Northern Europe, this is relevant. You may not be accumulating the 800+ hours per year of cold air exposure that elite skiers do, but a decade of winter riding with no protection adds up.
Protection that works
Face coverings. A Merino wool buff, thermal neck gaiter, or specifically designed cold-weather face mask worn over the mouth and nose pre-warms and humidifies inhaled air before it reaches the lower airways. The fabric traps moisture from your exhaled breath and uses it to condition the next inhalation. Research on winter sport athletes shows this reduces bronchospasm frequency by 40-60 per cent.
The practical limitation: at high intensities, any face covering restricts ventilation and can feel suffocating. Use it for Zone 2-3 riding in cold conditions. For hard efforts — intervals, climbs, group ride accelerations — pull it down. The benefit at moderate intensities, where you spend 80 per cent of your training time, is worth the mild inconvenience.
Intensity management in extreme cold. Below 0 degrees Celsius, consider limiting efforts to Zone 2-3 and saving hard intervals for the turbo trainer. The damage from cold air is proportional to ventilation rate — the harder you breathe, the more cold air reaches the lower airways. Thirty minutes of VO2max intervals at minus 3 degrees creates more airway stress than three hours of endurance riding at the same temperature.
Nasal breathing at low intensity. During Zone 1-2 riding, breathing exclusively through the nose is achievable for most trained cyclists. The nose warms air to body temperature, humidifies it to near 100 per cent relative humidity, and filters out particulate matter before it reaches the lungs. This is the most effective cold air conditioning system you have — and it costs nothing. At Zone 3 and above, supplement with mouth breathing as needed. Forcing nasal breathing above the ventilatory threshold restricts oxygen delivery and costs watts.
Respiratory muscle training: the $30 performance gain
We covered this in the breathing techniques guide, but it belongs here because it sits at the intersection of respiratory health and performance.
Your diaphragm and intercostal muscles fatigue during sustained hard efforts, just like any other muscle. When they fatigue, a reflex called the metaboreflex triggers your body to divert blood flow from working leg muscles to the respiratory muscles. This is your body prioritising breathing over pedalling — a sensible survival mechanism, but a costly one for performance.
Inspiratory muscle training (IMT) strengthens the respiratory muscles so they fatigue later in an effort. The tool is a handheld device — POWERbreathe, Ultrabreathe, and Airofit are the most common brands — that provides adjustable resistance when you inhale. You breathe against the resistance, and the diaphragm and intercostals adapt by getting stronger.
The protocol: 30 controlled breaths at approximately 50 per cent of your maximal inspiratory pressure, twice daily. Each session takes about 5 minutes. The breaths should feel like a hard set of strength training for the respiratory muscles — effortful but sustainable. Increase the resistance every 1-2 weeks as the muscles adapt.
The evidence: a meta-analysis of IMT studies in trained endurance athletes shows a 2-5 per cent improvement in time-trial performance, measurable reductions in perceived breathlessness at threshold, and a delay in the onset of the metaboreflex. These effects appear within 4-8 weeks of consistent training.
At less than $30 for a basic device and 10 minutes per day, this is one of the highest return-on-investment interventions available for a performance-focused cyclist. It also has a respiratory health benefit: stronger respiratory muscles mean more efficient breathing at all intensities, which reduces the ventilatory load per watt and decreases the volume of air (and pollutants) processed per unit of work.
Building a respiratory health protocol
None of this needs to be complicated. Four habits cover 90 per cent of the benefit:
One: Check air quality before riding outdoors. An AQI above 100 means train indoors.
Two: Choose quieter routes when possible. The difference between a busy road and a residential street is measurable and meaningful over thousands of training hours.
Three: Protect your airways in cold weather. A buff over the mouth for Zone 2-3 riding below 5 degrees. Save hard efforts for the trainer when temperatures drop below freezing.
Four: If you have a persistent post-exercise cough, unexplained limitation at high intensity, or wheezing in cold air, see a doctor and ask specifically for an EVH test or exercise challenge test. Do not accept "you just need to get fitter" as a diagnosis without investigation.
Your lungs are the only major organ in the performance chain that you cannot see on a training dashboard. No metric tracks their health. No graph shows their decline. But every watt, every FTP test, and every race result depends on their ability to deliver oxygen. Look after them the way you look after everything else.
And if you want to be around riders who take the full picture seriously — not just the training, but the health, the longevity, the performance over decades — the Roadman community on Skool is built for that conversation.