In asthma, high-intensity interval training (HIIT) reduces dyspnea and perceived fatigue better than constant-load exercise (CLE), but both types of physical activity produce comparable improvements in aerobic fitness, according to a study findings recently published in the Journal of Allergy and Clinical Immunology: In Practice.
High-intensity interval training — in which brief periods of demanding anaerobic exercise alternate with less demanding periods of recovery — is known to contribute to physical fitness in healthy adults; however, research into its effect on shortness of breath and overall fitness in people with asthma has been sparse. Constant-load exercise — which includes exercises such as weightlifting and push-ups that maintain a constant load on the body — has been shown to bestow many benefits on adults with asthma, including reduced hyperresponsiveness, anxiety, and depression, along with less need for corticosteroids.
In the current study, investigators based in Sao Paulo, Brazil, compared HIIT vs CLE with respect to their effects on dyspnea and clinical control in adults with moderate to severe asthma. The researchers conducted a randomized controlled trial (ClinicalTrials.gov Identifier: NCT02489383) that included 55 adults (N=55) between the ages of 20 and 59 years with a BMI of 35 kg/m2 or less and moderate or severe asthma. Participants were randomly assigned to undergo CLE training (N=27) or HIIT (N=28).
Participants performed CLE or HIIT training twice weekly for 12 weeks in 40-minute sessions. Although both types of training involved use of a stationary exercise bicycle, the expected exercise intensity levels (ie, the expected percentage of maximum workload [Wmax], as defined by cardiopulmonary exercise testing) and the method for improving Wmax varied for the HIIT and CLE training groups, as did the format of the training sessions.
Outcomes were evaluated using cardiopulmonary exercise testing, submaximal exercise testing (the Time Limit Test), the Asthma Control Questionnaire, the Asthma Quality of Life Questionnaire, the Hospital Anxiety and Depression Scale, and pulmonary function testing. Physical activity levels were assessed using an accelerometer, airway inflammation was calculated with a portable analyzer device, and systemic inflammation was measured using blood-based markers to test for interleukin and cortisol levels. At 12-week follow-up, clinical control, quality of life, physical activity levels, psychosocial distress, and lung function were reassessed.
Study data revealed that both exercise types induced comparable improvements in aerobic fitness. HIIT produced a bigger drop in dyspnea and fatigue perception, however. No alterations in systemic inflammation or psychosocial morbidity were seen. HIIT generated better outcomes in anxiety and depression symptoms, quality of life, and asthma control.
Study limitations included 8 participants who dropped out during the interventions, participant assessment at different times, and CLE equipment that differed from that used in previous research.
“This study shows the potential to include new models of physical training, such as HIIT, to the clinical treatment of asthma,” the authors affirmed.
Aparecido da Silva R, Rocco PGL, Stelmach R, et al. Constant-load exercise versus high-intensity interval training on aerobic fitness in moderate to severe asthma: a RCT. J Allergy Clin Immunol Pract. Published online May 30, 2022. doi:10.1016/j.jaip.2022.05.023