Background. Breathlessness in asthma often cannot be explained
with objective variables indicating
airways obstruction. The hypothesis that unrealistic breathlessness results
from false interpretation
of sensations was tested.
Methods. Sixty-four children and adolescents with asthma, aged
9–18 years, were randomly
assigned to: (1) standardized physical exercise for induction of general
symptoms; (2) equipment
causing itching through skin irritation; or (3) physical exercise combined
with equipment causing
itching through skin irritation. Pre-test and post-test measures were:
lung function; breathlessness;
general symptoms; itching; state anxiety; and worry.
Results. Lung function decreased within normal parameters (3·8%,
1·1%, 2·6%, respectively) and
did not differ significantly between conditions. Breathlessness increased
significantly after exercise,
particularly in condition 3. Breathlessness correlated with general symptoms
and worrying, but not
with changes in lung function, age, or asthma severity.
Conclusion. Biased symptom perception can explain unrealistic
breathlessness. Prerequisites are
situational cues triggering selective perception and ambiguous sensations
associated with the
anticipated (feared) physical state. Excessive breathlessness may often
warrant objective
confirmation by means of lung-function testing.