Factors associated with 6-min walk distance in severe asthma: A cross-sectional study.

BACKGROUND AND OBJECTIVE: Exercise capacity is associated with health-related quality of life and symptom control in severe asthma. Thus, interventions targeting exercise capacity are likely to be beneficial. However, clinical and biological factors impacting exercise capacity in severe asthma are sparsely investigated. We aimed to describe the association of selected clinical and biological factors with 6-min walk distance (6MWD) in adults with severe asthma and investigate the impact of sex on these outcomes. METHODS: A cross-sectional study in adults with severe asthma was conducted. Exercise capacity was measured by 6-min walk test, and association between 6MWD and predictors were evaluated using multiple linear regression. RESULTS: A total of 137 patients (females, 85; median age, 59 years) were recruited. Overall, asthma control (-15.2 m, 95% CI -22.6 to -7.7; p = 0.0001) and BMI (-3.2 m, 95% CI -5.1 to -1.3; p = 0.001) were significantly associated with exercise capacity (adjusted variance, adj. R2  = 0.425). In females, 5-item Asthma Control Questionnaire (ACQ-5; p = 0.005) and BMI (p < 0.001) were significantly associated with 6MWD (adj. R2  = 0.423). In males, a 0.5-point increase in ACQ-5 was associated with a decrease in 6MWD by 10.2 m (95% CI -22.8 to 2.4; p = 0.11), but no clinical nor biological factors reached statistical significance (adj. R2  = 0.393). CONCLUSION: Asthma symptoms and BMI were associated with exercise capacity in the overall population. Optimizing these factors may enhance the ability of patients to improve their exercise capacity and gain the associated positive health outcomes, but further studies are warranted.

Effect of aerobic exercise training on asthma in adults: a systematic review and meta-analysis.

OBJECTIVE: To evaluate the effect of aerobic exercise training on asthma control, lung function and airway inflammation in adults with asthma. DESIGN: Systematic review and meta-analysis. METHODS: Randomised controlled trials investigating the effect of ≥8 weeks of aerobic exercise training on outcomes for asthma control, lung function and airway inflammation in adults with asthma were eligible for study. MEDLINE, Embase, CINAHL, PEDro and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched up to April 3, 2019. Risk of bias was assessed using the Cochrane Risk of Bias Tool. RESULTS: We included 11 studies with a total of 543 adults with asthma. Participants' mean (range) age was 36.5 (22-54) years; 74.8% of participants were female and the mean (range) body mass index was 27.6 (23.2-38.1) kg·m-2. Interventions had a median (range) duration of 12 (8-12) weeks and included walking, jogging, spinning, treadmill running and other unspecified exercise training programmes. Exercise training improved asthma control with a standard mean difference (SMD) of -0.48 (-0.81--0.16). Lung function slightly increased with an SMD of -0.36 (-0.72-0.00) in favour of exercise training. Exercise training had no apparent effect on markers of airway inflammation (SMD -0.03 (-0.41-0.36)). CONCLUSIONS: In adults with asthma, aerobic exercise training has potential to improve asthma control and lung function, but not airway inflammation.

Can training induce inflammatory control in asthma, or is it symptom control only?

PURPOSE OF REVIEW: Exercise has shown to reduce asthma symptoms; however, the underlying mechanism for this improvement remains unclear. Improvement in inflammatory control could be the reason for this reduction in symptoms. This review discusses recent studies evaluating the effect of exercise on inflammatory control in patients with asthma. RECENT FINDINGS: New studies support that exercise is well tolerated and feasible regardless of intensity. Exercise seems to improve systemic low-grade inflammation, but consistency lacks when it comes to reduction in airway inflammation. SUMMARY: Physical exercise as an adjuvant therapy leads to improvement in asthma symptoms and asthma-related quality of life and should be recommended for all patients with asthma.

Effect of High-Intensity Interval Training on Inhaled Corticosteroid Dose in Asthma Patients: A Randomized Controlled Trial.

BACKGROUND: Inhaled corticosteroids (ICS) are the cornerstone of asthma treatment. However, ICS has side effects, and dose reduction is recommended when possible. Physical exercise improves asthma control, but it is unknown whether it reduces the reliance on ICS. OBJECTIVE: To assess whether supervised high-intensity interval training reduces the need for ICS in untrained asthma patients. METHODS: An assessor-blinded single-center randomized controlled trial, Copenhagen, Denmark. One hundred fifty untrained ICS-treated adults with symptomatic asthma were randomly assigned (2:1) to 6 months of supervised exercise 3 times weekly or a lifestyle as usual control group. Every second month, a clinical algorithm based on symptom control was applied in both groups to adjust ICS dose. Primary outcome was the proportion who had their ICS dose reduced by 25% or more after 6 months. Secondary outcomes included actual ICS dosage in micrograms per day. RESULTS: Between October 2017 and December 2019, 102 patients were allocated to exercise intervention (86% completed) and 48 to the control (85% completed). At the 6-month visit, 63% versus 50% met the primary outcome in the exercise and control groups, respectively (adjusted risk difference 9.6% [95% CI -3.8 to 18.8]; P = .15). Daily ICS dose was reduced in favor of the exercise group, with a mean difference of -234 µg (95% CI -391 to -77; P = .0037), corresponding to a 24% reduction from baseline. This effect was sustained at 12 months. The intervention was safe and well tolerated. CONCLUSIONS: Six months of regular exercise results in reduction in daily ICS dose without compromising asthma control.