RESPIRATORY FUNCTION, CARDIOVASCULAR DIMENSIONS AND WORK CAPACITY IN BOYS WITH BRONCHIAL ASTHMA

Abstract

Twenty boys with bronchial asthma, aged 8-13 yr, were studied regarding the size of their respiratory and circulatory organs and their exercise tolerance. The boys were divided into 2 groups (A and B) depending on the severity of their subjective symptoms. Normal values were found for TLC [total lung capacity], VC [vital capacity] and FRC [functional residual capacity] in both groups, but the group with the most severe asthma had a slightly increased RV [residual volume]. In both groups Hb, blood and heart volumes were normal. A normal relationship between these variables was observed also with work capacity [at heart rate of 170 beats/min.] (W170 and .ovrhdot.VO2 max [maximum O2 ventilization]), with no intergroup differences. Respiratory rate was lower and ventilation was increased in group B, both in submaximal and maximal exercise. Tidal volume in maximal exercise exceeded 50% of VC in this group. These boys also had the highest blood lactate concentration at submaximal and maximal exercise. In half of the boys, asthma-like attacks were elicited by the exercise. The symptoms subsided without treatment shortly after work. The frequency and intensity of attacks were similar in the 2 groups.