Competitive swimmers have asthma rates several times higher than the general population per published epidemiology. The Olympic-team data is dramatic; elite swimmers report asthma rates approaching 30 percent in some studies, compared to about 10 percent in the general adult population.
The mechanism is partly indoor-pool air quality, partly the breathing patterns of elite swimming, and partly self-selection (kids with asthma sometimes choose swimming as a sport because cold dry-air sports are worse for them).
For youth swimmers and parents, the practical implications are about indoor pool air quality and asthma management. The protocol below is what good programs do.
The chloramine problem.
Pools are chlorinated to control bacteria. Chlorine reacts with organic matter (sweat, urine, skin oils, lotions) brought into the pool by swimmers to form chloramines and other disinfection byproducts.
Chloramines are what gives indoor pools the “pool smell” most parents associate with cleanliness. The smell is actually the opposite indicator. A well-maintained pool with adequate fresh-water turnover and bather hygiene has minimal “pool smell.” A pool with strong chemical odor has high chloramine concentration.
Chloramines irritate airways, particularly when ventilation is poor. Symptoms include:
Coughing, especially after practice.
Wheezing in kids without prior asthma history.
Throat irritation, eye irritation, runny nose.
Triggering of asthma symptoms in kids with existing asthma.
Chronic exposure correlates with development of new asthma in some swimmers, particularly those training many hours per week in poorly-ventilated indoor pools.
The ventilation question.
Indoor pools with adequate ventilation maintain chloramine concentrations within levels that minimize respiratory effect. Pools with inadequate ventilation accumulate chloramines.
The signs of an inadequately-ventilated indoor pool:
Strong “pool smell” detectable from outside the natatorium.
Visible haze or mist over the water surface.
Condensation on windows, walls, or ceiling.
Coughing common among swimmers and lifeguards during practice.
The signs of an adequately-ventilated pool:
Minimal chemical odor.
Clear air above the water.
No condensation on building surfaces.
Quiet practices without persistent coughing.
USA Swimming’s facility-standards documentation includes ventilation expectations. Pools that meet them are uncommon in non-purpose-built facilities (some YMCA pools, some hotel pools, some school pools).
The asthma evaluation question.
For a youth swimmer with persistent post-practice coughing, wheezing, or breath difficulty:
Pediatrician evaluation. The pediatrician may refer to a pediatric pulmonologist or allergist.
The clinical workup typically includes:
History (specific to practice timing of symptoms, response to ventilation changes, family history).
Pulmonary function testing (PFT or spirometry). Often done both at rest and after exercise challenge.
Sometimes a methacholine challenge test to evaluate bronchial reactivity.
A swimmer diagnosed with exercise-induced asthma or chloramine-related asthma gets an Asthma Action Plan and typically rescue inhaler. Sometimes daily controller medication for moderate or severe cases.
The clinical distinctions worth knowing.
Exercise-induced bronchoconstriction (EIB). Airway narrowing during or after exercise. Common in swimmers. Treatable with pre-exercise inhaler.
Asthma with exercise as trigger. The kid has underlying asthma; exercise triggers it.
Chloramine-induced airway hyperreactivity. Specific to pool exposure. Symptoms improve away from the pool.
Each has different management. The pulmonologist makes the call.
For programs and facilities.
Ventilation maintenance. The HVAC system at the pool requires maintenance. Programs renting facilities should ask about ventilation standards and maintenance frequency.
Pre-practice showering rule. Bathers showering before entering the pool reduces organic load and therefore chloramine formation. Many facilities have the rule; few enforce it.
Restroom breaks for kids. Pool urination is the largest source of organic matter introduced during practice. Encouraged restroom breaks reduce the problem.
Chemical balance monitoring. Operators maintain free chlorine, combined chlorine (chloramines), and pH within standards. U.S. Centers for Disease Control and Prevention (CDC)‘s Model Aquatic Health Code provides the framework.
Water replacement. Periodic addition of fresh water dilutes chloramine accumulation. Skipping this saves operating cost and creates the chloramine accumulation problem.
For coaches.
Awareness of athletes’ breathing symptoms during practice. The kid coughing in lanes 30 minutes after the warm-up may have an asthma issue developing.
Communication with families about asthma history. The Asthma Action Plan should be on file with the team manager.
Practice modification on bad-air days. Indoor pools have variable air quality; some days are worse than others. A practice that produces multiple athletes coughing may need to be shortened or modified.
For parents.
For a kid with new-onset cough that correlates with swim practice, evaluation is appropriate.
For a kid with known asthma, the Asthma Action Plan should specifically address swimming. Pre-practice inhaler timing, post-practice monitoring, when to call the doctor.
Ask the program about pool air quality and ventilation. A program at a well-ventilated facility (such as a purpose-built competitive natatorium) has different air quality than a program at an aging YMCA pool.
The performance implications.
Asthmatic swimmers can compete at the highest levels. Many Olympic swimmers have asthma. The condition is manageable.
What worsens performance:
Uncontrolled asthma due to inadequate evaluation or medication compliance.
Practice in poor-air-quality pools producing repeated airway insult.
Reliance on rescue inhaler only without proper controller therapy when indicated.
What supports performance:
Properly diagnosed and managed asthma.
Pre-exercise warm-up that includes airway-preparation work.
Awareness of pool air quality and willingness to modify training on bad-air days.
The competitive-swimming long view.
Some research has suggested that competitive swimmers who train heavily in chlorinated pools through adolescence have lifetime elevations in asthma rates. The data is mixed but the pattern is documented enough to take seriously.
For a young swimmer with significant asthma symptoms or rapidly-developing respiratory issues, the conversation about long-term continuation of competitive swimming is reasonable.
For most kids with manageable asthma in well-run programs, swimming is a healthy lifelong activity. The risk-benefit calculation favors continued participation with proper management.
The honest read. Competitive youth swimming intersects with respiratory health in ways that purpose-built natatoriums handle well and aging facilities handle less well. The asthma rates in elite swimmers are real and partly explained by air quality. The management framework is established: ventilation standards at the facility level, hygiene rules at the bather level, clinical evaluation and treatment for symptomatic kids, and ongoing awareness by coaches and families.
For the family whose swimmer has new respiratory symptoms, the pediatrician evaluation is the right starting point. Most cases respond well to appropriate management.