Physical inactivity and bioimpedance analysis in treated asthmatic patients: a validated study using the sensewear armband

Rationale: Physical activity (PA) has been reported to be reduced in asthmatic patients. SenseWear system armband (SWA) (BodyMedia) is a system that continuously gather data estimating the wearer's caloric expenditure, METs and duration/intensity of PA. The Bioimpedance analysis (BIA) is a tool to estimate body composition. Studies with validated tools as SWA and BIA in adult asthmatic patients are missing. The aim of the present study was to investigate the physical activity in relationship to the pulmonary function, to the atopy and to the body composition in daily life of asthmatic patients. Methods: Patients with untreated intermittent asthma (UA, n=11), with moderate treated asthma (ICS, n=13) and healthy subjects (C, n=18) as control group were instructed to wear the SWA continuously (day and night) for four days. BIA was performed. Pulmonary function, atopy, ACT, ACQ, VAS, PNIF and smell test were also assessed. A non-parametric Kruskall Wallis and Mann Whitney test were applied, p<.05 was considered statistically significant. Results: The duration and intensity of PA, METs, FEV1 and FEV1/FVC were significantly lower (p=.005, p=.01, p=.03, p=.001 and p=.005 respectively) in ICS than in UA and in C. Furthermore the ACQ, ACT and VAS scores were significantly different (p=.04, p=.01 and p=.01 respectively) in ICS than in UA. In addition, FEV1 and atopy were significantly lower (p=.005) in UA and in ICS than in C. There were no significantly difference in PNIF and smell test as well in the body compartments (TBW, ICW, ECW, BCM, FM) and in time of wearing SWA among the studied groups. Conclusion: Despite no significant differences in the body composition were found among healthy and asthmatics, the intensity and duration of physical activity are daily reduced in moderate treated asthmatics. The SWA should be considered a useful tool for monitoring the progression of asthma disease.