Background: A majority of patients with asthma believe that psychological factors (particularly stress) can induce asthma attacks, but empirical support for actual stress-induced airways obstruction is controversial. This study tested the hypothesis that stress induces breathlessness and not airways obstruction.
Methods: Stress was induced by a frustrating computer task in 30 adolescents with asthma and 20 normal controls, aged 14-19 years. Stress measures were self-reported emotions, heart rate, blood pressure. Respiratory measures were respiratory rate (RR), end tidal CO2, deep inspirations and sighs. Asthma measures were lung function, wheeze, cough, breathlessness.
Results: All measures confirmed high levels of negative emotions and stress. None of the participants developed airways obstruction; they had no reduction in lung function, wheeze was absent and cough negligible. However, breathlessness increased in all participants with asthma and excessively in many. The mean breathlessness was higher than during induction of actual airways obstruction with provocative agents in previous studies. End tidal CO2 showed that breathlessness could not be explained by hypocapnia.
Conclusion: Stress can be sufficient to induce breathlessness in patients with asthma.