New findings suggest that HIIT may be an effective aerobic exercise option for asthma patients.
In patients with moderate to severe asthma, high-intensity interval training (HIIT) more effectively reduced dyspnea and perception of fatigue compared to constant-load exercise (CLE), according to new findings published in The Journal of Allergy and Clinical Immunology: In Practice.
Study investigators, led by Celso RF Carvalho, PT, FE, PhD, associate professor of physical therapy in the School of Medicine at the University of Sao Paulo, report that HIIT also improved quality of life and physical activity levels and reduced anxiety and depression levels as well.
Traditional approaches to management of asthma require both pharmacologic interventions, ie, inhaled corticosteroids and bronchodilators, and nonpharmacologic treatment, according to study authors. “Aerobic exercise is the nonpharmacological intervention with the most substantial evidence-based benefits, with increases in the [sic] physical activity reducing asthma exacerbations,” they write.
Carvalho and colleagues were specifically interested to learn how distinct types of aerobic exercise—HIIT or CLE—would affect symptoms of dyspnea and clinical control as well as emotional and quality of life (QoL) parameters in patients with asthma and significant disease burden.
The single-hospital study recruited at total of 55 adults with clinically stable, moderate or severe persistent asthma and randomized them into CLE (n=27) or HIIT (n=28) groups. The patients were between the ages of 20 and 59 years and had a mean body mass index of ≤35 kg/m2. After attending an educational program, participants began exercise training which required attending 24 sessions the prescribed HIIT or CLE exercise regimen over 12 weeks. Each 40-minute session included 5 minutes of warm-up, 30 minutes of exercise, and 5 minutes of cooldown, according to the study. Intensity of the exercise was increased every 2 weeks based on individual cardiopulmonary exercise testing results.
Before and after the exercise intervention, participants were evaluated for clinical asthma control (Asthma Control Questionnaire [ACQ]), systemic and airway inflammation, aerobic fitness (VO2 peak) heath-related QoL, physical activity levels (PAL), dyspnea, and symptoms of anxiety and depression. Investigators made comparisons using 2-way ANOVA and chi-square tests.
The researchers found that both HIIT and CLE increased VO2 peak and workload (P<.05) with no significant differences observed between groups. They also found no differences between groups in levels of dyspnea or lower limb fatigue after the interventions.
However, the study team reports, participants in the HIIT program experienced a reduction in dyspnea and lower limb fatigue during cardiopulmonary exercise testing between 4 and 10 minutes. Those engaged in CLE showed an improvement between 4 and 6 minutes but reported no significant change in fatigue perception.
Although participants in both groups experienced similar dyspnea levels, lower limb fatigue, and heart rate when evaluated during the exercise sessions, energy expenditure in the HIIT group was greater than that in the CLE group between the 10th and 24th sessions (P<.05).
After the intervention, the researchers found no clinically significant differences in ACQ results between HIIT and CLE groups (44% vs 35%) nor did they report differences in clinical control or lung function between groups during the 3-month follow-up period.
Interestingly, the investigators did find that similar proportions in the HIIT and CLE groups reported clinical reductions in levels of anxiety (63% and 53%) and depression (74% and 71%) during the active study although only the HIIT group maintained improvements through the follow-up period.
Overall, the authors conclude, CLE and HIIT were both effective in improving aerobic fitness among a population of adults with moderate to severe asthma, with the latter more effectively reducing dyspnea and limb fatigue as physical activity level increased.
In terms of clinical practice, they point out, the results demonstrate the potential to include new models of physical training in treatment for asthma. They also suggest a pragmatic study to assess how well patients may adhere to both types of exercise programs as a preferred regimen is more likely to be followed.
Reference: da Silva RA, Leite Rocco PG, 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. Published online May 29, 2022. DOI:https://doi.org/10.1016/j.jaip.2022.05.023