Comparing exercise responses to high intensity interval training between adults with and without asthma

Abstract

Exercise induced bronchoconstriction (EIBC) occurs in response to high ventilations during exercise, which cools and dries the airways, triggering an inflammatory cascade. High intensity interval training (HIIT) is associated with reductions in inflammation, improvements in cardiorespiratory outcomes, and mental health in healthy adults; however, the impact of HIIT in adults with EIBC is unclear. The purpose of this dissertation was to determine the impact of a 6-week HIIT intervention on physiological (e.g. inflammation, ventilation, and cardiorespiratory fitness) and psychological (i.e. anxiety) domains of health among adults with EIBC and healthy adults, and the impact of HIIT on clinical outcomes (i.e. asthma control) among adults with EIBC. METHODS: A quasi-experimental study design was used. A 6-week HIIT intervention was implemented in adults (18-44 years) with EIBC and healthy controls. Sessions were conducted three times per week and consisted of cycling at 10% PPO for 1 minute followed by 90% PPO for 1 minute, repeated 10 times. Primary measures at pre (T1) and post-intervention (T2) included: 1) maximal exercise test 2) passive drool saliva samples 3) anxiety sensitivity index-3 4) asthma control questionnaire-7 (EIBC group only). RESULTS: Participants in the EIBC group (n=20; T1: 32.9 ± 8.0; T2: 38.6 ± 8.2 ml/kg/min, p<0.01) and control group (n=12; T1: 38.6 ± 8.2; T2: 38.9 ± 12.3 ml/kg/min, p<0.01) improved VO2max. Adults with EIBC had lower levels of IL-1Ra at T2 when compared to healthy controls (EIBC T2: 0.2 ± 0.16pg/ug protein; Control T2: 0.8 ± 0.21pg/ug protein; p<0.01, hp2 = 0.3). Maximal ventilation in the EIBC group did not improve (EIBC T1: 97.8 ± 22.2; EIBC T2: 108.7 ± 29.5, p=0.7, Cohens d=0.4); however, the control group improved ventilation at the same absolute exercise workload (Control T1: 82.8 ± 20.1; Control T2: 101.8 ± 18.1, p=0.02). Reductions in anxiety sensitivity (EIBC T1: 17.9 ± 11.8; EIBC T2: 12.4 ± 13, p=0.002, Cohens d=0.4) and asthma control (EIBC T1: 0.8 ± 0.6; EIBC T2: 0.5 ± 0.4, p=0.02, Cohens d=0.5) from T1 to T2 occurred. CONCLUSION: A 6- week HIIT intervention leads to improvements in physiological, psychological, and clinical outcomes among adults with EIBC.