Effect of asthma treatment on fitness, daily activity and body composition in children with asthma

BACKGROUND: Although several cross-sectional studies have assessed the daily physical activity in children with asthma, the impact of the level of asthma control remains unknown. AIM: To assess the influence of asthma treatment-induced changes in asthma control on daily physical activity, cardiovascular fitness and body composition in children with asthma. METHODS: Daily accelerometer-measured physical activity, cardiovascular fitness, body composition (percent fat, percent lean tissue and bone mineral density) and a variety of asthma outcomes (to assess the level of asthma control) were measured over 4 weeks in 55 children with newly diagnosed untreated asthma and 154 healthy, sex and age-matched controls. Treatment with inhaled corticosteroids was initiated after the baseline period. All outcome measurements were repeated after 1 year and some also during the year of treatment. RESULTS: Asthma control improved markedly during the year of treatment. The improvement in control was associated with a significant increase in total daily activity of 2.8 h/week compared with the healthy controls (P < 0.001). In addition, significant increases were seen in moderate-vigorous activity (33 min/week; P = 0.01) and in cardiovascular fitness (1.2 ml O₂/min*kg) compared with the healthy controls. The improvement in activity was mainly seen during the last 6 month of the study. No difference was seen between the two groups in changes in percent body fat. CONCLUSION: Poorly controlled asthma is associated with reduced physical activity and cardiovascular fitness. Improvement in asthma control is associated with a clinically relevant increase in daily physical activity and cardiovascular fitness.