Dynamic hyperinflation and exercise limitations in obese asthmatic women

Abstract

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/m; n=36] and nonobese [nonobese group (NOb-G); BMI 18.5-29.9 kg/m; n=18] asthmatic patients performed a cardiopulmonary test to quantify peak V̇o 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 ( = 36) presented higher peak V̇o values but lower power-to-weight ratio values than the NOb-G ( <0 .05). DH was more common in the Ob-G (72.2%) than in the NOb-G (38.9%, < 0.05). The Ob-G had a greater reduction in the inspiratory capacity (-18 vs. -4.6%, < 0.05). Exercise tolerance was associated with quadriceps endurance ( = 0.65; p<0.001), oxygen pulse ( = 0.52; p=0.001), and DH ( = -0.46, = 0.005). The multiple regression analysis showed that the exercise tolerance could be predicted from a linear association only for muscular endurance ( = 0.82 and = 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. 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 (O 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.

Thoracoabdominal Asynchrony Contributes to Exercise Limitation in Mild Asthmatic Subjects

“…In asthmatic subjects, even under stable conditions, exercise responses may vary ( Del Giacco et al, 2015 ) due to an altered breathing pattern (i.e. increased respiratory rate, EEV, and rapid shallow breathing), thoracoabdominal asynchrony ( Tobin et al, 1983 ; Hillman et al, 1986 ; Lavietes et al, 1988 ; Upton et al, 2012 ) and fluctuation in airway caliber ( Barnes et al, 1981 ; Crimi et al, 2002 ; Kosmas et al, 2004 ; Ferreira et al, 2017 ), which may contribute to dyspnea and exercise limitation ( Aliverti, 2008 ). However, differently from COPD ( Aliverti et al, 2009 ; Priori et al, 2013 ; O’Donnell et al, 2017 ), little is known about the thoracoabdominal asynchrony and ventilatory responses in asthmatic subjects during exercise.…”

Effects of elastic tape on thoracoabdominal mechanics, dyspnea, exercise capacity, and physical activity level in nonobese male subjects with COPD

“…A Ն2-min interval was allowed between the maneuvers, and a minimum of four stable breaths was required before each IC maneuver. Assuming that total lung capacity remained constant during exercise, IC variations Ն10% from baseline were used to establish DH (9).…”

Dynamic hyperinflation impairs daily life activity in asthma

“…So, ongoing small airway inflammation might promote the development of dynamic hyperinflation and play a role in daily exercise limitations in subsets of asthma patients. Importantly, dynamic hyperinflation is found to be greater in obese versus nonobese asthma patients, whether or not related to reduced chest wall compliance, and therefore obesity has to be taken into account when evaluating dynamic hyperinflation in asthma [14]. Whatever the underlying mechanism, so far little is known about the prevalence of dynamic hyperinflation in moderate to severe asthma and in particular its impact on asthma symptoms, activities of daily life and perceived wellbeing.…”