Assessment of exercise capacity among asthmatic and healthy adolescents

To compare the physical performance and responses obtained in the six-minute walking test (6MWT) and the six-minute step test (6MST) between asthmatic and healthy adolescents; and to investigate the relationship between the responses obtained in the tests and the body mass index (BMI), physical activity level and spirometric variables.

Nineteen asthmatic adolescents (AG) and 19 healthy adolescents (HG) of both sexes, aged between 11 and 15 years, were assessed by means of spirometry, the 6MWT and the 6MST, and their physical activity levels were quantified using the International Physical Activity Questionnaire (IPAQ).

The AG had poorer physical performance, lower heart rate (HR) and greater lower-limb (LL) fatigue in the 6MST. In the 6MWT, the AG had positive correlations between walked distance (WD) and duration of intense activity, and between HR and BMI, whereas the HG had positive correlations between WD and HR and between WD and respiratory rate (RR). In the 6MST, the AG showed positive correlations between RR and maximum voluntary ventilation (MVV) and between duration of moderate activity and physical performance. The AG also showed negative correlations between physical performance in the 6MST and BMI, and between sensation of dyspnea and duration of walking. Also in the 6MST, the HG showed positive correlations between RR and MVV, and between BMI and LL fatigue (p < or = 0.05).

The 6MST demonstrated differences in exercise capacity between the asthmatic and healthy individuals. Furthermore, the physical performance and responses obtained in the tests were correlated with the MVV, BMI and physical activity level.