Effect of mild-to-moderate airflow limitation on exercise capacity

Abstract

To determine the effect of mild-to-moderate airflow limitation on exercise tolerance and end-expiratory lung volume (EELV), we studied 9 control subjects with normal pulmonary function [forced expired volume in 1 s (FEV1) 105% pred; % of forced vital capacity expired in 1 s (FEV1/FVC%) 81] and 12 patients with mild-to-moderate airflow limitation (FEV1 72% pred; FEV1/FVC % 58) during progressive cycle ergometry. Maximal exercise capacity was reduced in patients [69% of pred maximal O2 uptake (VO2max)] compared with controls (104% pred VO2max, P less than 0.01); however, maximal expired minute ventilation-to-maximum voluntary ventilation ratio and maximal heart rate were not significantly different between controls and patients. Overall, there was a close relationship between VO2max and FEV1 (r2 = 0.62). Resting EELV was similar between controls and patients [53% of total lung capacity (TLC)], but at maximal exercise the controls decreased EELV to 45% of TLC (P less than 0.01), whereas the patients increased EELV to 58% of TLC (P less than 0.05). Overall, EELV was significantly correlated to both VO2max (r = -0.71, P less than 0.001) and FEV1 (r = -0.68, P less than 0.001). This relationship suggests a ventilatory influence on exercise capacity; however, the increased EELV and associated pleural pressures could influence cardiovascular function during exercise. We suggest that the increase in EELV should be considered a response reflective of the effect of airflow limitation on the ventilatory response to exercise.

Determinants of Physical Fitness in Children With Asthma

“…Thus, we have reaffirmed earlier findings that were published more than a decade ago. 4,8,10 However, the most tantalizing findings dealt with the association between body weight and asthma, an association that has become the focus of more-recent interest and scrutiny. Obese children with asthma comprised nearly half of the study subjects and were overrepresented in the group who tallied higher scores when the degree of impairment due to asthma was calculated.…”

“…9 First, the degree of resting airflow obstruction could determine the ventilatory limits for aerobic exercise. 10 Second, the degree of bronchial hyperresponsiveness could impose limitations on exercise tolerance, an effect separate from baseline airway caliber. 11 Finally, the level of habitual activity could affect physical fitness, as is the case in healthy adults.…”

Índice prognóstico de mortalidade BODE e atividade física em doentes pulmonares obstrutivos crônicos

“…Pacientes que possuem grau de obstrução pulmonar elevado podem limitar as atividades físicas, porém a atividade física não exerce influência na variável VEF 1 dos indivíduos com DPOC (12)(13)(14) . Esse fato concorda com a literatura pertinente, reafirmando que a prática de exercícios aeróbios em programas de reabilitação não influenciam no grau de obstrução pulmonar e, sim, nos distúrbios secundários à DPOC (15) .…”

Lungs And Legs: Entrainment Of Breathing To Locomotion In Highly Trained Distance Runners

“…In contrast, individuals with pulmonary disease commonly exhibit pulmonary flow limitation, often experiencing it even at rest (Dueck, 2000). Babb et al (1991) found that 11 of 12 subjects with abnormal pulmonary function exhibited flow limitation during maximal exercise, with 7 of the 12 exhibiting some degree of flow limitation at rest.…”

“…Graphs can be generated for different intensities of exercise, with the tidal flow-volume loops produced during exercise plotted within a larger reference expiratory flow-volume loop obtained from a maximal breathing maneuver during rest. This method has been widely used to assess the degree of expiratory flow limitation and ventilatory constraint (Aaron et al, 1992;Babb et al, 1991;Chapman et al, 1998;Derchak et al, 2000;Grimby, 1969;Johnson et al, 1991aJohnson et al, ,b, 1992Johnson et al, , 1995Marciniuk et al, 1994;McClaran et al, 1999;Martinez et al, 1996;Mota et al, 1999;Regnis et al, 1996;Stubbing, 1980a). Indeed, Bye et al (1983) suggest that pulmonary flow-volume characteristics are perhaps the most important determinant of exercise limitation because of their implications for matching ventilation to metabolic demand.…”