Effects of Moderate- Versus Vigorous-Intensity Exercise Training on Asthma Outcomes in Adults

Background: The therapeutic effects of exercise have prompted calls for it to be embedded into standard asthma care, but evidence informing the optimal exercise intensity is lacking.

Objective: This study aimed to compare the effects of moderate- and vigorous-intensity aerobic exercise training on asthma outcomes and inflammation.

Methods: This was a 12-week randomized controlled trial in 46 adults with asthma randomized to either (1) 45-minute moderate-intensity exercise training 3 times/wk, (2) 30-minute vigorous-intensity exercise training 3 times/wk, or (3) the control group. Asthma-related quality of life (AQLQ), asthma control (ACQ), cardiorespiratory fitness, body composition, and airway and systemic inflammation were assessed before and after the intervention.

Results: Forty-one participants completed the study (89% retention). The moderate-intensity group had a statistically and clinically significant improvement in AQLQ (0.63 [0.33-0.93], P < .001) and ACQ (-0.51 [-0.83 to -0.19], P = .003) relative to control. The vigorous-intensity group had a statistically, but not clinically, significant improvement in AQLQ (0.46 [0.14-0.80], P = .007) and ACQ (-0.36 [-0.69 to -0.02], P = .040) relative to control. After moderate-intensity training, there was a reduction in sputum macrophage (-1341 [-2491 to -191] × 10⁴/mL, P = .024) and lymphocyte (-114 [-220 to -8] × 10⁴/mL, P = .036) counts relative to control. A reduction in android fat mass, but not a change in fitness, was associated with improved AQLQ (r_s = -0.341, P = .030) and reduced sputum IL-6 (r_s = 0.422, P = .013).

Conclusions: Our findings suggest that both moderate-intensity and vigorous-intensity aerobic exercise training are associated with improvements in clinical asthma outcomes and, therefore, both intensities could be recommended as an adjuvant asthma therapy.