Abstract
Transient airway narrowing can occur during or following exercise, a phenomenon called
exercise-induced bronchoconstriction (EIB). The main mechanism of EIB is considered
to be airway dehydration, resulting from increased ventilation during exercise. In
asthma, such water loss causes an increase in airway fluid osmolarity, inducing airway
smooth muscle contraction following the release of mediators from airway inflammatory
cells. Asthmatics frequently experience EIB, but it may also be observed in others
not reporting asthma symptoms, particularly elite endurance athletes. Individuals
with asthma often refrain from performing physical exercise because they fear troublesome
respiratory symptoms. However, in addition to its well-known cardiovascular and metabolic
benefits, physical training has been shown to be beneficial for asthmatic adults and
children in improving asthma control and asthma-related quality of life. Exercise
training also reduces the risk of asthma exacerbations, improves exercise capacity,
and decreases frequency and severity of EIB. To minimize the risk of EIB, asthma must
be well controlled, and specific pharmacological and nonpharmacological preventative
measures can be taken. Counterintuitively, in high-level athletes, the development
of asthma, airway hyperresponsiveness, and EIB can be promoted by intense training
over many years following exposure to environmental conditions, such as cold air,
pollutants, and allergens. As for nonathletes, athletes must have optimal asthma control
and apply preventative measures against EIB, taking into account antidoping regulations
for asthma medications. A better understanding of the impact of exercise on asthma
should improve the overall care of asthmatic patients.
Keywords
asthma - exercise - exercise-induced bronchoconstriction - physical training - athletes
