# Effects of constant-load exercise and high-intensity interval training on reliever medication consumption and peak expiratory flow in individuals with asthma: a randomised controlled trial PMID: 38469374 Journal: ERJ open research Published: 2024-03-11 Authors: da Silva RA, Cukier A, Carvalho-Pinto RM, Carvalho CRF ## Question Does constant-load exercise or high-intensity interval training better reduce short-acting beta2-agonist use and improve peak expiratory flow during a 12-week exercise program in individuals with moderate-to-severe asthma? ## Summary Adults with clinically stable moderate-to-severe asthma were randomized to 12 weeks of supervised cycling constant-load exercise or cycling HIIT. Both programs reduced pre-exercise reliever medication use and improved aerobic fitness and asthma control. HIIT produced higher post-exercise peak expiratory flow responses and reached the minimal clinically important difference for ACQ-6 asthma control, but the authors cautioned that whether HIIT is preferable for people with greater airway hyperreactivity needs confirmation. ## Population - Clinically stable adults aged 20-59 years with moderate-to-severe persistent asthma under medical treatment and pulmonologist monitoring. - Sample size: 55 - Age: CLE median 48.0 years; HIIT median 42.5 years - Sex: CLE 86% female; HIIT 83% female - Fitness level: Not currently exercising; baseline VO2peak about 88% predicted in both groups. - Health status: Moderate-to-severe persistent asthma, stable for at least 30 days, BMI <=35 kg/m2. ## Methodology - Randomized controlled trial; secondary analysis of a previous exercise trial focused on SABA consumption and PEF. - 12 weeks, 24 exercise sessions after a 4-hour educational program - University hospital exercise program in Sao Paulo, Brazil; supervised cycle ergometer training - Randomized and controlled study design. ## Protocol - HIIT. - Modality: Cycle ergometer. - Work intervals: 30 seconds. - Recovery: 30 seconds active recovery at 40% Wmax. - Sets or repetitions: Repeated rounds during a 30-minute exercise block; first four sessions lasted 20 minutes. - Intensity: 80-140% CPET-derived Wmax by program phase. - Session duration: 40 minutes planned: 5-minute warm-up, 30-minute exercise, 5-minute cool-down. - Frequency: 2 sessions per week. - Program length: 12 weeks. - Progression: Progressed from 80% Wmax to 140% Wmax across 12 weeks. - CLE. - Modality: Cycle ergometer. - Sets or repetitions: Continuous 30-minute exercise block. - Intensity: 60-80% CPET-derived Wmax, increased 5% every 2 weeks if effort, symptoms, and perceived exertion were appropriate. - Session duration: 40 minutes: 5-minute warm-up, 30-minute exercise, 5-minute cool-down. - Frequency: 2 sessions per week. - Program length: 12 weeks. - Progression: 5% intensity increase every 2 weeks when tolerated. ## Outcomes ### SABA consumption Status: improved In week 1, 30% of CLE and 21% of HIIT participants required SABA; in the last week, 3.7% of CLE and none of HIIT required SABA. Total pre- and post-exercise SABA consumption decreased over the intervention in both groups, without between-group difference. First versus last week reduction p<0.05; between-group difference p>0.05. ### Peak expiratory flow Status: improved CLE had a small persistent post-exercise PEF reduction, whereas HIIT had PEF values above baseline; HIIT's total area under the curve was 2.8 times greater than CLE. HIIT versus CLE p<0.05; all-session CLE PEF reduction p<0.05. ### Asthma clinical control Status: improved Both groups improved asthma control, but only the HIIT group reached the ACQ-6 minimal clinically important difference. ACQ-6 change CLE -0.23 +/- 1.06 versus HIIT -0.52 +/- 0.73; HIIT within-group p<0.05. ### Aerobic fitness Status: improved Both groups improved aerobic fitness and reached the reported MCID for VO2peak; CLE had greater effect size for VO2peak, while HIIT had greater effect sizes for work rate, PEF, and ACQ-6. VO2peak percent change reported in abstract as CLE 10.1 +/- 12.8% versus HIIT 5.7 +/- 15.6%; both reached >=1.0 mL/kg/min MCID. ## Practical Insights - A 30-second on/30-second off HIIT cycling protocol can be progressed over 12 weeks in clinically stable adults with moderate-to-severe asthma under supervision. - For asthma-sensitive programming, gradual progression and a short adaptation phase are important parts of the protocol, not incidental details. - HIIT may be more airway-friendly than continuous cycling for some asthma patients, but this should be framed as supervised clinical evidence rather than a general consumer guarantee. ## Limitations - Secondary analysis; SABA and PEF sample-size calculation was difficult because prior studies had not assessed those outcomes after exercise training. - Small sample size and special clinical population. - Supervised cycle-ergometer setting with CPET-derived intensity limits direct translation to unsupervised bodyweight HIIT. - No long-term follow-up after intervention was reported. - Supplementary figures were referenced but not used as extraction sources. ## Safety And Adherence - No adverse events or injuries were explicitly reported in the extracted full text. - PEF monitoring before and after sessions was used to guide SABA use. - Participants with PEF below 70% threshold were advised to use two 100 microg salbutamol doses. - Clinical exclusions limit translation to higher-risk asthma patients or those with cardiovascular/musculoskeletal disease. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/38469374/) (pubmed) - [DOI](https://doi.org/10.1183/23120541.00899-2023) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10926009/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.