Exercise-induced bronchoconstriction

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

During intense exercise, high minute ventilation cools and dries the airway surface. In susceptible airways the subsequent osmotic and mediator response narrows smooth muscle, producing a measurable post-exercise fall in FEV1. Cold dry environments, high-ventilation endurance activity, pollutants and allergens can accentuate the response. Symptoms may include cough, expiratory wheeze, chest tightness or disproportionate breathlessness during recovery, but there is no symptom pattern specific enough to make the diagnosis alone.

The diagnostic question is not simply whether exercise causes breathlessness, but which physiological system limits exercise. Reproducing the person's usual intensity and environment can matter. Standard exercise challenge, eucapnic voluntary hyperpnoea or another indirect challenge may be selected by a respiratory physiology or sports-respiratory service. Spirometry is measured at baseline and at defined recovery points; a laboratory-defined reproducible fall supports EIB. Peak flow or a subjective response to salbutamol is not an adequate stand-alone test.

Treatment should enable exercise rather than promote avoidance. When EIB accompanies asthma, current UK care prioritises inhaled corticosteroid-containing treatment and a written plan. Technique and adherence are reviewed before escalation. Persistent symptoms despite suppression of bronchoconstriction should reopen the differential, especially exercise-induced laryngeal obstruction, breathing-pattern disorder, anaemia and cardiovascular limitation.

Key points

Exercise-induced bronchoconstriction is a transient fall in expiratory airflow after exertion; it is common in asthma but can occur without otherwise typical chronic asthma.
Symptoms alone perform poorly: exertional cough, wheeze and breathlessness also arise from inducible laryngeal obstruction, dysfunctional breathing, poor fitness, obesity, cardiac disease and anaemia.
EIB often peaks shortly after intense exercise, particularly in cold dry air; inspiratory noise and throat tightness at peak exercise favour exercise-induced laryngeal obstruction.
Confirm the diagnosis with spirometry before and serially after a standardised exercise or indirect bronchial challenge, using the laboratory's validated protocol and interpretation criteria.
Baseline spirometry may be normal and does not exclude EIB; conversely, resting obstruction should prompt standard asthma assessment and safe planning before challenge.
In a person with asthma, recurrent EIB often signals inadequate anti-inflammatory control, poor adherence or technique, so review the whole asthma regimen rather than adding pre-exercise reliever indefinitely.
Warm-up, gradual conditioning, trigger management and protection from cold dry air support participation but do not replace inhaled corticosteroid when asthma is present.
For people using AIR or MART, preventive use of the prescribed ICS-formoterol may be appropriate under the exact product and asthma action plan.
A SABA can prevent predictable EIB in a person whose plan includes inhaled corticosteroid, but frequent preventive reliance indicates the need for control review.
Elite athletes must also check current anti-doping rules and therapeutic-use documentation; ordinary prescribing advice does not guarantee competition compliance.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Underlying asthma

Exercise commonly exposes incompletely controlled asthma, with airway hyperresponsiveness producing transient post-exertional narrowing, with the final risk shaped by exposure and individual susceptibility.

Cold dry air

High ventilation of cold, low-humidity air increases airway heat and water loss, particularly during endurance winter sport.

Irritants and allergens

Pollution, chlorine by-products and seasonal aeroallergens amplify epithelial stress and bronchial responsiveness in susceptible athletes, and several contributors may coexist in the same patient.

Elite training exposure

Repeated extreme ventilation can injure airway epithelium and produce bronchoconstriction even without conventional chronic asthma features.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Airway water loss
Rapid mouth breathing during exercise bypasses nasal conditioning and dehydrates the airway surface, contributing to the resulting loss of respiratory reserve.
2
Osmotic mediator release
Airway-surface hyperosmolarity activates epithelial and inflammatory cells, releasing mediators that contract bronchial smooth muscle, and the downstream physiological effect determines clinical severity.
3
Rewarming response
Post-exercise airway rewarming and vascular engorgement may add mucosal narrowing after ventilation slows, which links the underlying lesion to the observed respiratory dysfunction.
4
Transient airflow limitation
The combined response causes cough, chest tightness and expiratory obstruction during or shortly after exertion, usually resolving between episodes.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Typical post-exercise bronchoconstriction

Cough, expiratory wheeze, chest tightness or dyspnoea develops during sustained high ventilation or soon after stopping, then recovers spontaneously or with an appropriate bronchodilator.

Under-controlled asthmaRed flag

Exercise symptoms accompany night waking, variable daytime symptoms, increasing reliever use, attacks or poor inhaled corticosteroid use. EIB is then a control signal rather than an isolated sporting problem.

Exercise-induced laryngeal obstruction

Abrupt inspiratory difficulty, throat tightness or high-pitched noise at peak effort with rapid resolution after stopping favours a laryngeal mechanism; asthma and laryngeal obstruction can coexist.

Non-airway exertional limitationRed flag

Early fatigue without airflow change, chest pain, syncope, palpitations, desaturation or systemic symptoms should prompt evaluation for fitness, anaemia, cardiac disease, pulmonary vascular disease or another cause.

Exercise-associated anaphylaxisRed flag

Breathlessness with urticaria, angioedema, hypotension or gastrointestinal symptoms is not ordinary EIB and requires immediate anaphylaxis treatment and emergency assessment, including possible food or drug cofactors.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Quality-assured baseline spirometry with bronchodilator testingFirst step
Why
Identify resting obstruction and broader variable airflow disease.
Interpretation and limitations
Normal baseline spirometry does not exclude EIB. Obstruction or convincing reversibility supports asthma assessment and may make unsupervised high-intensity challenge inappropriate until the person is clinically stable.
02
Standardised exercise challenge with serial post-exercise FEV1
Why
Demonstrate reproducible exercise-triggered expiratory airflow reduction.
Interpretation and limitations
The protocol must achieve adequate ventilation and capture the recovery window. Interpret the greatest reproducible FEV1 fall using validated laboratory criteria; a submaximal or environmentally dissimilar test can be falsely negative.
03
Indirect bronchial challenge such as eucapnic voluntary hyperpnoea
Why
Replicate airway drying when standard exercise testing is unavailable or insensitive.
Interpretation and limitations
Specialist protocols and serial spirometry are required. A positive indirect challenge supports airway hyperresponsiveness but should still be integrated with the clinical setting and alternative exercise limitation.
04
FeNO, eosinophils and current asthma objective-test sequence
Why
Assess whether EIB sits within type 2 inflammatory asthma.
Interpretation and limitations
Inflammatory markers may support an asthma phenotype but do not confirm exercise-related narrowing. Inhaled or systemic corticosteroid can lower results, so timing and background treatment must be recorded.
05
Continuous laryngoscopy during exercise
Why
Confirm exercise-induced laryngeal obstruction during reproduced symptoms.
Interpretation and limitations
Dynamic glottic or supraglottic closure at peak exercise supports EILO. Resting laryngoscopy may be normal and does not exclude an inducible event.
06
Cardiopulmonary exercise testing and targeted blood tests
Why
Define non-airway limitation when challenge findings are discordant.
Interpretation and limitations
Ventilatory, cardiac, gas-exchange and effort patterns can distinguish deconditioning or dysfunctional breathing from circulatory limitation; full blood count and other tests follow the clinical differential.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Inducible laryngeal obstruction

Abrupt inspiratory noise and throat tightness at peak exercise, resolving quickly on stopping, favours dynamic laryngeal closure.

Poor fitness or obesity

Expected breathlessness without objective post-exercise airflow change suggests ventilatory demand and deconditioning rather than bronchoconstriction, with targeted examination and testing used to resolve the uncertainty.

Cardiac disease

Exertional chest pain, syncope, arrhythmia or abnormal cardiac testing requires cardiovascular assessment rather than an asthma assumption.

Dysfunctional breathing

Erratic breathing, tingling and disproportionate symptoms with normal airway tests suggest a breathing-pattern disorder after organic causes are assessed.

Anaemia

Fatigue, pallor and reduced exercise capacity without wheeze or airflow change may reflect impaired oxygen carriage.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01HistorySeparate timing and soundFirst stepBreathlessness, cough or noisy breathing is repeatedly associated with exercise.

1Describe exact activity, intensity, environment, onset relative to peak effort, inspiratory versus expiratory noise, throat or chest sensation and recovery time.
2Ask about asthma outside exercise, attacks, inhaler use, allergic triggers, food or medicine cofactors, cardiac symptoms and training history.
3Identify emergency features such as syncope, chest pain, systemic allergy or prolonged severe distress and investigate those before elective bronchial challenge.
4Arrange baseline spirometry and an objective provocation strategy rather than using a therapeutic trial as the only diagnostic evidence.

02ChallengeReproduce physiology safelyThe person is stable and objective confirmation of EIB will change management.

1Select exercise or indirect challenge with the physiology service, accounting for the person's sport, environment, baseline airflow and medicine-withholding instructions.
2Check baseline clinical stability and spirometry, explain stop criteria, and ensure trained staff and rescue bronchodilator are immediately available.
3Achieve the validated exercise or ventilation target, then obtain serial FEV1 through the expected recovery period rather than one late measurement.
4Interpret magnitude, reproducibility and symptom concordance; if symptoms occur without bronchoconstriction, investigate laryngeal, breathing-pattern, cardiac or conditioning causes.

03ConfirmedEnable activity with controlObjective testing supports EIB or asthma with exercise-related loss of control.

1Explain that exercise remains desirable and agree warm-up, gradual conditioning, cold-air strategies and trigger reduction relevant to the person's goals.
2For asthma, optimise current NICE inhaled corticosteroid-containing therapy, technique and adherence, and incorporate exercise prevention into the written action plan.
3Use the prescribed AIR/MART inhaler or an appropriate pre-exercise bronchodilator exactly as licensed and planned, checking frequent need as a marker of poor control.
4EscalationReview response using participation and objective control; persistent limitation despite improved airway physiology requires reassessment rather than escalating bronchodilator repeatedly.

04Competitive sportPrescribe within sporting rulesThe person competes under an anti-doping code or elite programme.

1Confirm the governing body and current prohibited-list status because permitted inhaled drug amounts and documentation can change.
2Record objective diagnosis and prescribed regimen, involving sports medicine or the governing body's medical process when therapeutic-use documentation is required.
3AlternativeDo not alter clinically necessary treatment solely from informal anti-doping advice; verify the official current rule and plan a compliant alternative where possible.

Key medicines and prescribing safety3 treatments · regimens, roles and cautions

Provide rapid bronchodilation together with inhaled corticosteroid treatment for asthma-related exercise symptoms.

Budesonide-formoterol anti-inflammatory reliever

Use one inhalation as needed from the exact product and strength prescribed for AIR, including pre-exercise use when agreed in the personalised plan.

Only products licensed and locally selected for AIR or MART should be used this way. Observe product-specific maximum inhalations; frequent preventive or rescue use indicates inadequate control and requires prompt asthma review.

Prevent or relieve exercise-related bronchoconstriction when SABA is the chosen reliever strategy.

Inhaled salbutamol before predictable exercise

A licensed adult regimen is 200 micrograms inhaled ten to fifteen minutes before challenge, within a plan that also supplies inhaled corticosteroid treatment.

SABA must not be the only asthma treatment. Frequent reliance, reduced protection, palpitations or tremor should trigger review; check device technique and the exact product licence, and follow emergency advice when usual relief fails.

Provide an oral leukotriene-receptor antagonist option within stepped asthma management, sometimes reducing EIB.

Montelukast add-on treatment

For adults and people aged fifteen or over, the licensed dose is 10 mg orally once daily in the evening when clinically selected.

Benefit is variable and it does not replace inhaled corticosteroid or acute rescue treatment. Discuss sleep, mood, behaviour and other neuropsychiatric reactions before prescribing and advise prompt medical review if they occur.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Avoidance and deconditioning

Fear of symptoms can reduce physical activity, worsening fitness, weight and confidence despite exercise remaining beneficial with appropriate care.

Unrecognised poor asthma control

Treating exercise symptoms in isolation can miss persistent airway inflammation and a broader risk of severe exacerbation.

Severe bronchospasm

Occasionally, intense exercise provokes marked airflow obstruction and respiratory distress, particularly when baseline asthma is uncontrolled.

Inappropriate treatment

Misdiagnosed laryngeal, cardiac or functional symptoms may lead to unnecessary escalation of asthma medicines while the true mechanism persists.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Track the exercise intensity and environment at which symptoms begin, time to recovery and whether participation improves, not merely the number of inhaler actuations.
Review daytime and night asthma symptoms, reliever use, attacks, oral corticosteroid courses, adherence and technique because isolated exercise treatment can conceal broader poor control.
Repeat objective challenge when diagnosis remains doubtful, symptoms change substantially or elite documentation requires it, following safe medicine-withholding instructions.
For montelukast, ask specifically about new sleep, mood, behaviour or cognitive symptoms and reassess whether a meaningful clinical benefit justifies continuation.
If bronchodilation suppresses FEV1 change but breathlessness persists, monitor for inspiratory noise, dysfunctional breathing, anaemia, cardiac symptoms and training mismatch.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Timing localises the problem

EIB commonly manifests after sustained ventilation or early recovery, whereas EILO often peaks at maximal effort and resolves quickly. The distinction guides which dynamic test should reproduce symptoms.

A fit person can be ill

High baseline lung volumes and performance do not exclude EIB. Interpret spirometry against appropriate reference limits and reproduce the actual ventilatory demand rather than comparing with sedentary expectations.

Warm-up can create protection

Some people experience a refractory period after interval warm-up, but variable benefit means it should complement, not replace, an anti-inflammatory asthma plan.

Negative challenge quality matters

A challenge that fails to generate sufficient ventilation, uses warm humid air or samples FEV1 too late may miss disease. Review protocol adequacy before declaring symptoms non-respiratory.

Treat participation as an outcome

The aim is safe, confident exercise with fewer symptoms and attacks. Avoidance can worsen conditioning and make breathlessness more prominent even if airway inflammation improves.

11Common pitfallsFrequent interpretation and management errors.

01
Diagnosing EIB from exertional breathlessness alone without demonstrating post-challenge airflow change.
02
Calling inspiratory stridor at peak effort asthma and repeatedly escalating beta2 agonists.
03
Using salbutamol before every activity indefinitely while ignoring poor inhaled corticosteroid adherence and broader asthma symptoms.
04
Declaring a low-intensity or poorly timed challenge negative without checking whether adequate ventilation and serial spirometry were achieved.
05
Telling a person to stop exercising rather than enabling safe participation and investigating the true limiter.
06
Assuming a prescribed inhaler is automatically permitted under the athlete's current competition rules.