The effect of mouth breathing on exercise induced fall in lung function in children with allergic asthma and rhinitis

Exercise induced bronchospasm (EIB) represents a common feature of childhood asthma which is most commonly revealed during free running. On the other hand aerobic exercise shows significant beneficial effects in asthmatics especially on the reduction of the level of systemic inflammation and is recommended as part of its treatment. The aim of this study was to test how mandatory mouth breathing influences the exercise induced level of decrease in lung function according to the level of severity of allergic rhinitis (AR).

Free 6-minute running test preceded and followed by spirometry done with and without a nose clip a day apart was conducted in 55 children with moderate persistent asthma and AR. Children were divided into two groups according to the severity of nasal symptoms.

There was a greater fall in forced expiratory volume in one second after exercise with a nose clip in children with less nasal symptoms than in children with more nasal symptoms (mean ± SD; -5.28 (7.91) vs. -0.08 (4.58), p = 0.0228) compared to testing without the nose clip (mean ± SD; LNS, -1.31 ± 3.89%, p = 0.2408; MNS, -1.47 ± 3.68%, p = 0.2883).

Our results show that regular mouth breathing due to nasal congestion may lessen the degree of EIB in patients with persistent AR and allergic asthma.