Dyspnea Intensity, Descriptors, And Negative Symptoms During Exercise In Obese And Nonobese Children

Abstract

PURPOSE: The purpose of this study was to examine dyspnea intensity, descriptors, and associated negative symptoms during exercise in 10 and 11 year old obese and nonobese children. METHODS: 12 obese (9 boys, age: 11.3 ± 0.6y, height: 149.7 ± 6.7cm, mass: 65.8 ± 14.4kg, BMI percentile: 97.5 ± 1.4, body fat: 46 ± 3%) and 11 nonobese (5 boys, age: 10.8 ± 0.5y, height: 143.3 ± 5.2cm, mass: 35.8 ± 3.8kg, BMI percentile: 50.3 ± 21.5, body fat: 27 ± 6%) underwent 3 constant load exercise tests for 6 minutes each (at 40W, 50% of VO2max, and 50% of VO2max + 20W), and a maximal exercise test. Ratings of perceived breathlessness (RPB), ratings of perceived exertion (RPE), top 3 descriptors related to dyspnea, and negative symptoms related to dyspnea (unpleasantness, depression, anxiety, frustration, fear, and anger) on a visual analog scale (VAS) were measured. Also, parents reported whether their child gets short of breath with exertion during the screening process to ascertain whether the child experienced dyspnea on exertion (DOE) outside the laboratory. RESULTS: 58% of obese children complained of DOE outside of the laboratory, compared to only 9% of nonobese children (P = 0.013). RPB and RPE were not different between obese and nonobese children during each submaximal exercise test for both absolute and relative work rates (P > 0.05). Nonobese children picked 13 out of 15 descriptors of dyspnea within their top 3 during cycling at 40W, with 30% of nonobese children expressing that their “breathing required work”. In contrast, obese children picked only 7 (i.e. they felt they were breathing more, their breathing was heavy, rapid, and shallow, required work/effort, and they had difficulty with inhalation). Unpleasantness associated with dyspnea on the VAS scale was higher in nonobese children while cycling at 40W compared with obese children (3.0 ± 1.5 vs. 0.8 ± 0.5; P = 0.001), although relative exercise intensity was similar between groups (P = 0.842). CONCLUSIONS: At both relative and absolute exercise intensities, RPB and RPE were not different between obese and nonobese 10 and 11 year old children. Surprisingly, negative symptoms related to dyspnea were actually greater in the nonobese children. This suggests that obese children are able to tolerate moderate to vigorous intensity exercise to the same extent as nonobese children.