EXT was shown to improve asthma symptoms, QoL, exercise capacity, BHR, EIB, and FEV1 in asthmatics and improvements in BHR explained part of the improvement in QoL and exercise capacity. Thus, physical activity should be recommended as a supplementary therapy to medication. However, more well controlled studies should be performed assessing the relationship of physical activity, QoL, airway hyperreactivity, lung function and especially airway inflammation as well as medication intake.

Background: The beneficial effects of exercise training for asthmatics might relate to repetitive airway stretching. Thus, a training with more pronounced airway stretch using isolated, volitional hyperpnea (HYP) might be similarly or more effective. However, in healthy subjects, a bout of HYP training is known to cause an acute FEV₁ decline. Objective: The aim of the present study was therefore to test whether these changes are more pronounced in asthmatics, possibly putting them at risk with HYP training. Methods: Nine subjects with mild-moderate asthma (confirmed by mannitol challenge) and 11 healthy subjects performed six 5-min bouts (with 6-min breaks; HYP₁) and one 30-min bout (HYP₂) of normocapnic HYP at 60% of maximal voluntary ventilation using warm and humid air. FEV₁ and airway resistance (R5) were measured before, in breaks (HYP₁), and immediately after HYP, and during 60 min of recovery. Results: In both groups, a significant and similar decrease in FEV₁ during HYP₁ (asthmatics: –3 ± 3%; healthy subjects: –2 ± 3%), after HYP₁ (asthmatics: –2 ± 5%; healthy subjects: –1 ± 4%), and after HYP₂ (asthmatics: –4 ± 5%; healthy subjects: –3 ± 3%), and an increase in R5 during and after both HYPs were observed. Maximal changes in FEV₁ and R5 did not correlate with baseline lung function or responsiveness to mannitol. Conclusions: A bout of HYP does not lead to relevant bronchoconstriction and the observed changes in lung function and airway resistance are neither of the magnitude of clinical relevance, nor do they differ from responses in healthy individuals. Thus, HYP training can safely be tested as an airway-specific exercise training alternative (or add-on) modality to regular aerobic exercise training.

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