Breathlessness during exercise: 61% of the teenagers who report it have no asthma diagnosis

Breathlessness during exercise affects 14% of 12-13 year-olds, with higher risk in girls, and 61% of those reporting it have no asthma diagnosis (Johansson et al., 2014, Swedish sample). When adolescents are objectively tested, estimated prevalence is 19.2% for exercise-induced bronchoconstriction and 5.7% for exercise-induced laryngeal obstruction (Johansson et al., 2015). Symptoms alone can't tell the two apart: that takes an objective test.

14% of adolescents report attacks of breathlessness after strenuous activity, and the risk is higher in girls — yet 61% of them have no asthma diagnosis at all (Johansson et al., 2014). When you actually measure, that single symptom splits into at least two different conditions — one in the bronchi, one in the larynx — treated in opposite ways. Here's what the evidence says, and why 'she's just unfit' is the most expensive conclusion available.

A fourteen-year-old stops halfway through a drill, hands on her knees, and says she can't get any air in. Two minutes later her breathing is normal and she's back on court. The same thing happens the following Tuesday. The explanation that arrives first is almost always one of three: it's anxiety, she's unfit, or it's asthma — and with asthma comes an inhaler, often without anyone having measured anything. The data say all three explanations can be wrong, and that beneath that symptom sit at least two different conditions, distinguishable only by testing and treated in opposite ways.

In brief

  • 14% of 12-13 year-olds report attacks of breathlessness after strenuous activity; female sex is independently associated with higher risk (Johansson et al., 2014, Swedish sample).
  • 61% of those reporting the symptom have no asthma diagnosis: it is a common and largely uninvestigated symptom (Johansson et al., 2014).
  • With objective testing in the adolescent population, estimated prevalence is 19.2% for exercise-induced bronchoconstriction (EIB) and 5.7% for exercise-induced laryngeal obstruction (EILO), which can coexist (Johansson et al., 2015).
  • Diagnosing EIB requires a fall in FEV1 of ≥ 10% on objective testing: symptoms alone have low sensitivity and specificity (Parsons et al., 2013; Goldin and Bruner, StatPearls, 2025).
  • For EILO the reference standard is laryngoscopy during the symptomatic episode, and validated treatment algorithms are not yet established (Halvorsen et al., 2017).

How common is exercise-induced breathlessness in adolescent girls?

Far more common than the number of diagnoses suggests. In a Swedish population study, 2,309 adolescents aged 12-13 answered a questionnaire on respiratory symptoms: 14% reported at least one attack of shortness of breath after strenuous physical activity in the past year, and multivariate analysis identified female sex — along with rhinitis and a history of asthma — as independently associated with the symptom (Johansson et al., 2014, Respiratory Medicine).

The detail that changes the reading is a different one: 61% of those reporting the symptom had no asthma diagnosis at all. This isn't a population of already-monitored girls who keep struggling; it's a population of girls struggling without anyone having looked. And they weren't less active than their peers: the study found no significant difference in physical activity levels between those reporting the symptom and those who weren't. They trained anyway, out of breath.

If it isn't asthma, what else can it be?

Once you move from questionnaire to measurement, the symptom splits in two. In the same research project, 3,838 adolescents completed questionnaires and 146 underwent standardised treadmill exercise testing with continuous laryngoscopy during exercise. Estimated prevalences in the total population were 19.2% for exercise-induced bronchoconstriction (EIB) and 5.7% for exercise-induced laryngeal obstruction (EILO), with both able to coexist in the same person (Johansson et al., 2015, Thorax).

These are two problems at two different points in the respiratory tract:

Exercise-induced bronchoconstriction (EIB) Exercise-induced laryngeal obstruction (EILO)
Where Lower airways, the bronchi Larynx, at throat level
When Typically after exertion, peaking within 10-15 minutes Typically at peak exertion
How it resolves Usually within 30-90 minutes, then a refractory period of 1-3 hours Quickly on stopping
How it's documented Fall in FEV1 of ≥ 10% on objective testing Laryngoscopy during the symptomatic episode

The timings and the refractory period for EIB are described in the clinical reference chapter by Goldin and Bruner (StatPearls, 2025); the diagnostic standard for laryngeal obstruction comes from the joint statement of the European respiratory and laryngological societies (Halvorsen et al., 2017, European Respiratory Journal).

The difference isn't specialist trivia. A bronchodilator acts on the bronchi: there is no reason for it to work on a larynx that closes. An athlete with EILO treated as asthmatic can spend seasons with an inhaler she doesn't need, convinced — along with her coach — that the problem is in her head.

Why do so many girls end up with the wrong diagnosis?

Because the diagnosis is often made by listening rather than measuring. Reviews of dyspnoea in athletes note that asthma and EIB are frequently diagnosed on symptoms alone, without pulmonary function testing, and that numerous studies have documented athletes treated with bronchodilators who later tested negative objectively (Smoliga et al., 2016, Breathe). The clinical reference chapter is blunt about it: outside patients with established asthma and typical symptoms, a clinical diagnosis based on symptoms alone has low sensitivity and specificity (Goldin and Bruner, StatPearls, 2025).

On EILO, reviews describe it as more frequent in females and in adolescence, with a prevalence around 5% in the athletic population rising to as high as 35% among athletes referred for dyspnoea evaluation (Smoliga et al., 2016). Precision matters here: in the Swedish population study that objectively tested adolescents from the general population, no significant differences emerged between girls and boys for either EIB or EILO (Johansson et al., 2015). What is documented more robustly is that girls report the symptom more often (Johansson et al., 2014).

It's a distinction worth holding onto, because it usually gets used backwards. That girls report breathlessness more often isn't evidence that they're more fragile: it's the reason their symptom deserves the same seriousness, instead of being filed under emotion — the same mechanism that leads to minimising female athletes' pain.

How do you get to a real diagnosis?

With two different examinations, because the two conditions become visible in two different ways.

For exercise-induced bronchoconstriction, the American Thoracic Society clinical practice guideline builds diagnosis on objective testing — exercise challenge or eucapnic voluntary hyperpnoea — not on the account given (Parsons et al., 2013, Am J Respir Crit Care Med). The reference threshold is a fall in FEV1 of 10% or more from baseline, with severity grading rising at 25% and 50%; some centres use 15% as a more specific threshold (Goldin and Bruner, StatPearls, 2025).

For laryngeal obstruction, the joint ERS/ELS statement identifies laryngoscopy performed during the symptomatic episode as the reference standard — in practice, continuous laryngoscopy while the athlete exercises. The same document is explicit about the limits of the evidence: validated diagnostic and treatment algorithms are not yet established, and the review identified no randomised controlled trials (Halvorsen et al., 2017).

It's worth telling a family plainly: this isn't a five-minute test at the family doctor's, and in many places the pathway runs through a respiratory physician or a sports medicine centre. But it's the only way to know whether that inhaler is doing anything.

What can be done when the diagnosis is EILO?

The first tool isn't a drug — which is also why this condition gets taken less seriously. Non-surgical options described in the literature include breathing advice, speech therapy, biofeedback and inspiratory muscle training. The ERS/ELS statement reports them while noting at the same time that supporting randomised controlled trials are lacking (Halvorsen et al., 2017).

The evidence closest to the athletes we're discussing comes from a Norwegian study of 18 adolescent athletes — 17 girls, aged 13-19 — followed for five months with a multidimensional intervention combining Norwegian psychomotor physiotherapy, elements of cognitive behavioural therapy and an individualised rehabilitation plan. Afterwards, participants reported less respiratory distress during high-intensity exercise, less anxiety about their breathing difficulties and a greater sense of control, with a shift in breathing pattern from thoracic to diaphragmatic — with no significant change in measured lung function (Kolnes et al., 2024, BMC Sports Science, Medicine and Rehabilitation).

Two caveats, both important. First: the study had no control group and no randomisation, so it shows an association, not demonstrated efficacy. Second: the fact that lung function didn't change doesn't mean the symptom was imaginary — it means the mechanism wasn't in the lungs, which is exactly where this article started.

When is it genuinely just fitness?

It can be. But that's a conclusion, not a starting point. The differential diagnosis of exercise-induced breathlessness in athletes includes, beyond EIB and EILO, dysfunctional breathing, exercise-induced hyperventilation, lung disease other than asthma, cardiac causes and deconditioning (Smoliga et al., 2016). There's also a frequent and population-specific cause that presents as tiredness and breathlessness rather than wheeze: iron deficiency in adolescent female athletes.

The problem with starting from 'she's unfit' is that it's a self-confirming explanation: the athlete trains harder, feels worse, concludes she isn't cut out for it, and stops. It's one of the quiet routes to dropping out of sport during puberty — not a dramatic event, but a run of sessions in which a girl decides, on her own, that this sport isn't for her.

What a club can do, starting Monday

None of these is a clinical procedure. They're observations and organisational choices:

BAB's role

BAB doesn't diagnose, doesn't run spirometry and doesn't replace a respiratory assessment. It does the thing that's missing between one session and the next: it gives the athlete a way to report privately how her breathing went — whether she stopped, when, how long it lasted — and gives the club aggregate signals, never individual data, that make visible a pattern which otherwise lives only in one person's memory.

That 61% of adolescents with breathlessness and no diagnosis didn't emerge from clinical intuition: it emerged because somebody asked 2,309 teenagers the question and counted the answers. At the scale of one squad the principle is identical: a symptom nobody records doesn't exist, until the day the athlete stops.

Sources

This article is for information only and is not medical advice or a clinical assessment. Breathlessness during exercise should be assessed by a clinician: if it appears at rest, or comes with chest pain, fainting or blue lips, or doesn't settle on stopping, it needs urgent assessment rather than watchful waiting.

How many girls experience breathlessness during training?

More than get recognised. In a Swedish sample of 2,309 adolescents aged 12-13, 14% reported at least one attack of shortness of breath after strenuous physical activity in the previous twelve months, and female sex was independently associated with higher risk (Johansson et al., 2014). The more telling figure is a different one: 61% of those reporting the symptom had no asthma diagnosis at all. In adolescent girls, exercise-induced breathlessness is first and foremost an uninvestigated symptom.

Is breathlessness during sport always asthma?

No, and that's the most common confusion. When a population study moved from questionnaires to laboratory exercise testing, two distinct conditions emerged: exercise-induced bronchoconstriction (EIB), which involves the lower airways, with an estimated prevalence of 19.2%, and exercise-induced laryngeal obstruction (EILO), which involves the larynx, with an estimated prevalence of 5.7% in the adolescent population (Johansson et al., 2015). The two can also coexist in the same athlete. They sound identical when described — 'I can't get any air in' — but they are anatomically different problems, and they respond to different treatments.

What's the difference between exercise-induced asthma (EIB) and EILO?

Location and timing. In exercise-induced bronchoconstriction the lower airways narrow typically after exercise: it peaks within 10-15 minutes of stopping and usually resolves within 30-90 minutes, followed by a refractory period of 1-3 hours (Goldin and Bruner, StatPearls, 2025). In exercise-induced laryngeal obstruction the narrowing is at the throat, tends to appear at peak exertion, and resolves quickly on stopping. This is a practical distinction, not an academic one: a bronchodilator acts on the bronchi, and there's no reason for it to work on a larynx that closes.

Why does the inhaler sometimes not work?

Because in a share of cases the diagnosis was never verified. Reviews note that asthma and EIB are frequently diagnosed in athletes on symptoms alone, without pulmonary function testing, and that a number of athletes treated with bronchodilators later test negative on objective testing (Smoliga et al., 2016). If an athlete uses her inhaler and is still breathless, that's useful clinical information — not evidence that she isn't trying. It belongs back with whoever made the diagnosis.

How are exercise-induced asthma and EILO actually diagnosed?

With a measurement, not with a description. For exercise-induced bronchoconstriction, diagnosis rests on an objective test — exercise challenge or eucapnic voluntary hyperpnoea — with a fall in FEV1 of 10% or more from baseline (ATS guideline, Parsons et al., 2013; Goldin and Bruner, StatPearls, 2025). For laryngeal obstruction, the reference standard is laryngoscopy performed during the symptomatic episode, meaning while the athlete is exercising, not at rest (joint ERS/ELS statement, Halvorsen et al., 2017). Outside of patients with established asthma and typical symptoms, diagnosis on symptoms alone has low sensitivity and specificity (Goldin and Bruner, StatPearls, 2025).

Is EILO more common in girls?

The honest answer has two halves. Reviews describe exercise-induced laryngeal obstruction as more common in females and in adolescents, with a prevalence around 5% in the athletic population and up to 35% among athletes referred for dyspnoea evaluation (Smoliga et al., 2016). But in the population study that objectively tested adolescents, neither EIB nor EILO showed significant differences between girls and boys (Johansson et al., 2015). What is documented more robustly is that girls report the symptom more often (Johansson et al., 2014) — which makes investigating it, rather than attributing it to nerves, more important, not less.

What can be done if it is exercise-induced laryngeal obstruction?

The first step isn't pharmacological. Options described in the literature include breathing retraining, speech therapy, biofeedback and inspiratory muscle training, but the joint ERS/ELS statement notes that validated diagnostic and treatment algorithms are not yet established and that no randomised controlled trials were identified (Halvorsen et al., 2017). A study of 18 adolescent athletes (17 girls, aged 13-19), with no control group and no randomisation, observed after five months of multidimensional intervention a reduction in respiratory distress and in anxiety about breathing, with no significant change in lung function (Kolnes et al., 2024). That's a signal, not proof of efficacy.

What if she really is just unfit?

She might be, but that's a conclusion to reach at the end, not the beginning. The differential diagnosis of exercise-induced breathlessness includes, beyond EIB and EILO, dysfunctional breathing, lung disease other than asthma, cardiac causes and simple deconditioning (Smoliga et al., 2016). Iron deficiency, which is common in adolescent female athletes, can also present as fatigue and breathlessness on exertion. Starting from 'she's unfit' closes the investigation before it opens — and it's one reason many girls quit instead of being assessed.

What should a coach do when an athlete stops, out of breath?

Observe and record, don't interpret. Note when the breathlessness appears (during or after exertion), how long it lasts, whether the noisy breathing is louder on the way in or on the way out, and whether an inhaler, if there is one, makes a difference: those are exactly the observations the bronchi-versus-larynx distinction is built on. Then refer for medical assessment. What a coach shouldn't do is close the subject in two words — 'anxiety', 'poor fitness', 'you just need to run more' — because a non-trivial share of these girls have a condition that a test can document.