Physical activity and asthma: The role of obesity

Physical activity is recommended for youths and adults with asthma. Asthma and physical activity individually has been associated with body mass index (BMI), and BMI may play an important role in the relationship between them. The objective of this study was to determine the association between Leisure Time Physical Activity (LTPA) and asthma status stratified by BMI levels among youths and adults in a nationally representative sample. We also explored the relationship between LTPA and asthma morbidity. Data for persons aged 16–45 years (N=7040) from the National Health and Nutrition Examination Survey 2001–2004 were analyzed. Associations between asthma status (i.e., current, previous, or never) and LTPA, as measured in metabolic equivalent (MET)-minutes, were determined using multivariate linear regression procedures stratified by BMI levels (<25 vs. ≥25). Log-linear models were used to determine the association between LTPA and asthma morbidity (e.g., wheezing). Overweight and obese individuals (BMI ≥25) with current asthma had 29% (95% confidence interval = 2%, 48%; p=0.04) fewer LTPA MET-minutes than those who never had asthma. No significant differences were observed in LTPA by asthma status among the overall study population and individuals with BMI <25. LTPA was also not associated with having asthma attacks or the number of wheezing episodes in the last 12 months. Overweight and obese persons with asthma are less active than their counterparts without asthma. However, LTPA was not associated with asthma morbidity in this cross-sectional sample. Increased PA should be emphasized in the asthma management plan for overweight and obese persons with asthma.