ABSTRACT
BACKGROUND: The effects of high-intensity interval training (HIIT) on dyspnea and aerobic fitness in adults with asthma are poorly understood. OBJECTIVE: To compare constant-load exercise (CLE) versus HIIT for improvements in dyspnea symptoms and clinical control in adults with moderate-to-severe asthma. METHODS: Participants were randomized into 2 groups: CLE (n = 27; started with 70% of maximal watts [Wmax] obtained during cardiopulmonary exercise testing [CPET]) and HIIT (n = 28; started with 80% and increased until 140% Wmax). Exercise training lasted 12 weeks (twice/week, 40 minutes/session on a cycle ergometer), and the intensity was based on CPET. Clinical asthma control (Asthma Control Questionnaire), aerobic fitness (the peak of oxygen uptake), health-related quality of life (Asthma Quality of Life Questionnaire), physical activity levels (PAL; accelerometer), symptoms of anxiety and depression (Hospital Anxiety and Depression Scale questionnaire), and dyspnea were evaluated before and after the intervention. Systemic and airway inflammation were also assessed. Two-way analysis of variance and χ2 tests were used for comparisons. Sixteen participants dropped out during the interventions and returned for the final evaluations. RESULTS: The CLE and HIIT groups showed similar improvements in aerobic fitness. The HIIT group had lower dyspnea and fatigue perception scores and higher PAL than the CLE group (P < .05) and clinical improvements in the psychosocial distress. In addition, only the HIIT group achieved a minimal clinically important difference in asthma symptoms. There was no change in the systemic and airway inflammation (P > .05). CONCLUSION: Both interventions promoted similar improvements in aerobic fitness; however, HIIT induced a greater reduction in dyspnea and fatigue perception. Similar responses were observed for other variables.
