High-intensity interval training benefits patients with asthma

Constant-load exercise and high-intensity interval training improved aerobic fitness in adults with moderate to severe asthma, although the latter method offered more benefits, according to a recent study.

“Patients and physicians frequently ask what type of exercise people with asthma most benefit from,” Celso R.F. Carvalho, PT, FE, PhD, associate professor at University of São Paulo School of Medicine, told Healio.

Celso R.F. Carvalho

“At this moment, almost all studies have evaluated the effect of aerobic training. On the other hand, high-intensity interval training (HIIT) is a novel exercise training method, and several exercise training clinics have stimulated patients to perform it,” Carvalho said.

Published in The Journal of Allergy and Clinical Immunology: In Practice, the study involved 55 patients treated at a hospital with clinically stable moderate or severe persistent asthma aged 20 to 59 years.

Each patient underwent evaluation for clinical asthma control, health-related quality of life, psychosocial morbidity, cardiopulmonary exercise testing, physical activity level, and airway and systemic inflammation.

Next, researchers assigned 27 patients to constant-load exercise (CLE) and 28 to HIIT. Training included 40-minute sessions on a cycle ergometer twice a week for 12 weeks.

Sessions included 5 minutes of warmup, 30 minutes of exercise and 5 minutes of cooldown. Exercise intensity increased every 2 weeks based on each participant’s cardiopulmonary exercise testing results.

Using cardiopulmonary exercise testing, researchers found that both exercise interventions led to comparable increases in participants’ peak oxygen uptake and workload, with no differences between the groups in dyspnea levels or lower limb fatigue after the interventions.

“We did not expect that HIIT would induce similar benefits to those observed by aerobic exercise,” Carvalho said.

After the intervention, the HIIT group achieved an increase of at more than 500 steps a day — the level established to show a minimal clinically important difference — in total physical activity level during weekdays compared with the CLE group (P < .05), which also reflected an increase compared with baseline (P < .003), although this improvement was not observed during follow-up.

Compared with the CLE group, the HIIT group experienced reductions in dyspnea levels during the physical test limit (minutes 2 to 4) after the interventions (P < .05). The groups did not experience any differences in lower limb fatigue.

After the first 2 weeks, both groups maintained dyspnea and fatigue levels between “somewhat hard” and “hard.” Similar dyspnea levels, lower limb fatigue and heart rates during the exercise sessions also were observed among both groups, although the HIIT group expended more energy than the CLE group between sessions 10 and 24 (P < .05).

Also, after the intervention, the researchers did not find any clinically significant differences in Asthma Control Questionnaire 6 (ACQ-6) results between the HIIT and CLE groups (44% vs. 35%), although the HIIT group displayed a minimal clinically important difference in ACQ-6 scores compared with baseline. Similarly, the researchers did not observe any differences during the follow-up in clinical control or lung function in both groups.

However, similar proportions of the HITT group and CLE group experienced clinical reductions in anxiety (63% vs. 53%) and clinical reductions in depression levels (74% vs. 71%), although only the HIIT group saw these symptoms improve through the follow-up period.

Additionally, there were no changes in inflammatory asthma biomarkers, including IL-1B, IL-17, TNF-alpha, IL-2, IL-10, MCP-1 and RANTES (Regulated on Activation, Normal T Cell Expressed and Secreted) as well as cortisol.

Overall, the researchers concluded that CLE and HIIT both effectively improved aerobic fitness among adults with moderate to severe asthma, with HIIT providing better results in reducing dyspnea levels and limb fatigue while increasing physical activity level.

“These findings allow the recommendation of HIIT to people with asthma,” Carvalho said.
“Also, they suggest that people with asthma can do other types of exercise training.”

The results of this study additionally open two new fronts, Carvalho continued.

First, a pragmatic study should evaluate how well patients with asthma adhere to CLE and HIIT exercise programs.

“The importance is to assess which exercise patients prefer,” he said.

Second, he said, studies should assess which type of exercise reduces the incidence of exercise-induced bronchoconstriction, which is a condition where patients present dyspnea with exercise.

For more information:

Celso R.F. Carvalho, PT, FE, PhD, can be reached at cscarval@usp.br.