High-intensity interval training (HIIT) also improved quality of life and physical activity levels while reducing anxiety and depression levels.
High-intensity interval training (HIIT) is an effective training model for improving aerobic fitness and reducing dyspnea levels and lower limb fatigue in patients with moderate to severe asthma, according to a study published in The Journal of Allergy and Clinical Immunology: In Practice.
HIIT was more effective at reducing dyspnea levels and lower limb fatigue and increasing physical activity levels (PAL) compared with constant-load exercise (CLE), researchers found.
Asthma management traditionally requires both pharmacological treatments, such as inhaled corticosteroids and bronchodilators, and nonpharmacological treatment. “Aerobic exercise is the nonpharmacological intervention with the most substantial evidence based benefits with increases in the physical activity, reducing asthma exacerbations,” the authors wrote.
Adults with asthma treated at a hospital with clinically stable, moderate, or severe persistent asthma between the ages of 20 and 59 were studied.
A total of 55 adults with clinically stable, moderate, or severe persistent asthma were randomized into CLE (n=27) or HIIT (n=28) groups. The patients were between the ages of 20 and 59 years, had a body mass index of ≤ 35 kg/m2, and had been treated at a hospital. Participants attended an educational program prior to their exercise program, which required attending 24 sessions of respective exercise programs over a 12-week period.
Both interventions were found to increase the peak of oxygen uptake (VO2peak) and workload (P < .05) without differences between groups (P > .05). There were no differences found between the groups in dyspnea levels and lower limb fatigue after the interventions. (P > .05).
However, the HIIT participants experienced a reduction in dyspnea and lower limb fatigue during cardioplumary exercise testing between 4 and 10 minutes. The participants in CLE showed an improvement between 4 and 6 minutes but reported no significant change in fatigue perception.
Though both groups presented similar dyspnea levels, lower limb fatigue, and heart rates when evaluated during the exercise sessions (P > .05), energy expenditure in the HIIT group was greater than that in the CLE group between the 10th and 24th sessions (P < .05).
No differences were observed in clinical control or lung function for both groups in the 3-month follow-up period.
In both CLE and HIIT groups, similar proportions of participants observed a reduction in anxiety (63% vs 53%) and depression levels (74% vs 71%) after the interventions; however, these symptoms were only improved in the HIIT group during the 3-month follow-up period. Reduction in anxiety could be due to the reduction of dyspnea induced by HIIT, the authors speculated.
Similarly, only HIIT showed clinical improvements in the total score and in the symptoms related to emotional function that lasted 3 months after the intervention.
Generally, the effect size was greater for HIIT with 7 out of 9 outcomes in favor of HIIT. CLE reached higher outcomes for VO2peak and work rate. Only HIIT participants were shown to improve in moderate PAL and reach clinical improvement for asthma control and health-related quality of life.
The authors noted that further studies are needed to evaluate whether HIIT can be used to improve PALs in association with behavior intervention.
These findings conflict with previous research demonstrating that participants of CLE achieve clinically significant better asthma control. However, the authors suggest these discrepancies are due to some CLE participants having good asthma control at baseline and difference in exercise modality from previous studies.
While both CLE and HIIT improve aerobic fitness for patients with asthma, the findings suggest that HIIT is more effective in reducing dyspnea and fatigue symptoms.
“As the effects of CLE and HIIT were similar in several outcomes, our findings suggest that HIIT may be an alternative exercise training model to be performed for participants with moderate to severe asthma,” the authors concluded.
Da Silva RA, 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