Patricia D. Freitas

The Role of Exercise in a Weight-Loss Program on Clinical Control in Obese Adults with Asthma A Randomized Controlled Trial

Rationale: Clinical control is difficult to achieve in obese patients with asthma. Bariatric surgery has been recommended for weight loss and to improve asthma control; however, the benefits of nonsurgical interventions have been poorly investigated. Objectives: To examine the effect of exercise training in a weight‐loss program on asthma control, quality of life, inflammatory biomarkers, and lung function. Methods: Fifty‐five obese patients with asthma were randomly assigned to either a weight‐loss program plus exercise (WL + E group, n = 28) or a weight‐loss program plus sham (WL + S group, n = 27), where the weight‐loss program included nutrition (caloric restriction) and psychological therapies. The WL + E group incorporated aerobic and resistance muscle training, whereas the WL + S group incorporated breathing and stretching exercises. Measurements and Main Results: The primary outcome was clinical improvement in asthma control over 3 months. Secondary outcomes included quality of life, lung function, body composition, aerobic capacity, muscle strength, and inflammatory/antiinflammatory biomarkers. After 3 months, 51 patients were analyzed. Compared with the WL + S group, the WL + E group demonstrated improved clinical control scores (median [25th to 75th percentile], −0.7 [−1.3 to −0.3] vs. −0.3 [−0.9 to 0.4]; P = 0.01) and greater weight loss (mean ± SD, −6.8% ± 3.5 vs. −3.1% ± 2.6; P < 0.001) and aerobic capacity (median [25th to 75th percentile], 3.0 [2.4 to 4.0] vs. 0.9 [−0.3 to 1.3] ml O2 × kg−1 × min−1; P < 0.001). These improvements in the WL + E group were also accompanied by improvements in lung function, antiinflammatory biomarkers, and vitamin D levels, as well as reductions in airway and systemic inflammation. Conclusions: Adding exercise to a short‐term weight‐loss program should be considered as a useful strategy for achieving clinical control of asthma in obese patients. Clinical trial registered with www.clinicaltrials.gov (NCT 02188940).

Dynamic hyperinflation and exercise limitations in obese asthmatic women

Obese individuals and patients with asthma can develop dynamic hyperinflation (DH) during exercise; however, no previous study has investigated DH as a factor associated with reduced exercise capacity in obese asthmatic women. The aim of the present study was to examine the occurrence of DH and exercise limitations in obese asthmatics. Obese grade II [obese group (Ob-G); BMI 35-39.9 kg/m2; n=36] and nonobese [nonobese group (NOb-G); BMI 18.5-29.9 kg/m2; n=18] asthmatic patients performed a cardiopulmonary test to quantify peak V̇o2 and a submaximal exercise test to assess DH. Anthropometric measurements, quadriceps endurance, and lung function were also evaluated. A forward stepwise regression was used to evaluate the association between exercise tolerance (wattage) and limiting exercise factors. Fifty-four patients completed the protocol. The Ob-G (n = 36) presented higher peak V̇o2 values but lower power-to-weight ratio values than the NOb-G (P <0 .05). DH was more common in the Ob-G (72.2%) than in the NOb-G (38.9%, P < 0.05). The Ob-G had a greater reduction in the inspiratory capacity (-18 vs. -4.6%, P < 0.05). Exercise tolerance was associated with quadriceps endurance (r = 0.65; p<0.001), oxygen pulse (r = 0.52; p=0.001), and DH (r = -0.46, P = 0.005). The multiple regression analysis showed that the exercise tolerance could be predicted from a linear association only for muscular endurance (r = 0.82 and r2 = 0.67). This study shows that dynamic hyperinflation is a common condition in obese asthmatics; they have reduced fitness for activities of daily living compared to nonobese asthmatics. However, peripheral limitation was the main factor associated with reduced capacity of exercise in these patients.NEW & NOTEWORTHY This is the first study to investigate the occurrence of dynamic hyperinflation (DH) in obese asthmatics. Our results demonstrate that obese asthmatics present a higher frequency and intensity of DH than nonobese asthmatics. We also show that physical deconditioning in this population is linearly associated with cardiac (O2 pulse), respiratory (DH), and peripheral muscle (resistance) limitation. However, multiple linear regression demonstrated that peripheral muscle limitation may explain the exercise limitation in this population.