The acute effects of high intensity interval exercise on pulmonary function and exhaled nitric oxide in adults with asthma

Introduction: People with asthma suffer from lower fitness levels when compared to their peers. The abnormal respiratory response to exercise, known as exercise induced bronchoconstriction (EIB), in the majority of people with asthma is a barrier to improving fitness levels. EIB severity can be increased with airway inflammation, which can be measured by exhaled nitric oxide (eNO). One exercise protocol, high intensity interval exercise (HIIE), may decrease the risk of developing EIB in people with asthma. HIIE warm up studies have demonstrated that HIIE is feasible and reduces the incidence of EIB in subsequent exercise bouts. HIIE may be ideal for people with asthma because it can decrease the duration of high ventilation that can trigger EIB, and improve their fitness levels. The purpose of this study is to compare the acute respiratory effects of traditional constant workrate exercise to a novel HIIE protocol in adults with asthma. Methods: 5 females and 2 males with asthma were recruited to perform two randomly assigned exercise protocols: HIIE (30 seconds of 140% the peak workrate and 90 seconds at 20%) and constant workrate exercise (CWR) (60% peak workrate). Workrates were determined by a peak cardiopulmonary exercise test. Measures of pulmonary function and airway inflammation were done pre and post exercise protocols. During exercise protocols, operational lung volumes, heart rate, rating of perceived exertion (RPE) was obtained. Results: FEV1 decreased significantly in both exercise protocols (HIIE 3.91± 0.65 to 3.33 ± 0.61 vs. CWR 3.90 ±0.50 to 3.09 ± 0.63). eNO measurements decreased after both exercise protocols (HIIE 40.4± 34.8 vs. CWR 42.1 ± 36.3. Conclusion: FEV1 and eNO findings are similar in HIIE and CWR exercise in adults with asthma, therefore, the novel HIIE is a feasible exercise protocol to help improve fitness levels of adults with asthma