Daytime physical activity levels in school-age children with and without asthma.

Background: Physical activity (PA) is a significant predictor of health outcomes in children with and without chronic conditions. Few researchers have used actigraphy as an objective measure of PA during the child's normal daily routines, and the findings have been inconsistent. It is unclear if asthma can contribute to low PA levels.

Objectives: The aim of this study was to compare daytime PA levels in children with and without asthma and examine the relationships among asthma, PA, body mass index (BMI), and child reports of symptoms.

Methods: Physical activity as measured by actigraphy and self-report symptoms of coughing, wheezing, chest tightness, perceived tiredness, sleepiness, and alertness were obtained in 54 children aged 9-11 years with and without asthma for 7 consecutive days. Activity variables derived from actigraphy included (a) mean daytime activity level; (b) peak daytime activity level; and (c) time duration spent in sedentary, light, moderate, vigorous, and total moderate plus vigorous PA (MVPA).

Results: Children with and without asthma did not differ on BMI or activity levels. Children with asthma reported more activity limitations due to breathing problems than children without asthma (p < .01). In multivariate analyses, asthma predicted reduced mean, peak, and total time spent in MVPA level after controlling for gender, BMI, and self-report of symptoms. A significant interaction was found between asthma and BMI on mean, peak, and total time spent in MVPA.

Discussion: The association between asthma and PA is complex when the child's BMI is considered. Results suggest that reduced PAs with respect to respiratory symptom severity, childhood obesity, and functional impairment are important areas for future studies.