Physical activity and sedentary time in severe asthma: Key clinical associations

Published online: November 10, 2017

Severe asthma is a heterogeneous and complex disease, where poor disease control and health status are common findings. This high symptom burden is likely to have a negative impact on the levels of physical activity and sedentary time that people with severe asthma engage in. Inactivity and sedentary time are recognized risk factors for the development of several chronic diseases and premature mortality. Additionally, higher levels of activity have been associated with better asthma clinical outcomes in people with mild to moderate asthma. In severe asthma, however, inactivity and sedentary time have not been widely studied, nor has the relationship between these behaviours and clinical and biological outcomes of the disease.

In a recently published article in JACI: In Practice, Cordova-Rivera and colleagues characterized the level of physical activity and sedentary time in a severe asthma population and in age- and gender-matched controls, and examined how these behaviors relate to different clinical and biological outcomes of the disease such as exercise capacity, airflow limitation, and systemic and airway eosinophilic inflammation. Physical activity and sedentary time were measured for 14 consecutive days using a tri-axial accelerometer worn on the hip.

The authors found that the population with severe asthma participated in significantly lower levels of at least moderate activity, accumulating 31% fewer steps per day than controls (P=0.0002), and almost 50% fewer daily minutes of moderate and vigorous physical activity (P<0.0001). However, they had higher levels of light physical activity (P=0.03). No significant differences were found for sedentary time. The authors also found that in severe asthma, higher levels of physical activity were associated with better exercise capacity and asthma control as well as lower levels of systemic inflammation, even after adjusting for sedentary time, which means that despite the time spent sedentary, physical activity is still associated with an improvement in these outcomes.

Physical activity impairment is prevalent in severe asthma. Addressing physical inactivity and sedentary time may be a potential nonpharmacological approach in the management of severe asthma.

