B ODY M EDIA S ENSE W EAR A RMBAND Physical Activity Monitor

M EASURING P HYSICAL A CTIVITY Physical Activity: Any bodily movement by skeletal muscles resulting in energy expenditure. As discussed already in class, there are two ways to measure physical activity based off this definition. Movement Energy Expenditure (Physiological Response)

B ODY M EDIA SWA What makes this monitor so accurate and the “Gold Standard” physical activity monitoring device? The SWA measures both movement and physiological response. Important to note that the SWA still ESTIMATES energy expenditure – its still not a direct measure (DLW)

M ULTI - SENSORY D EVICE The SWA has three sensors to monitor physical activity: Accelerometer: Maria has already talked about Heat Flux: Measure the amount of heat your producing and how quickly your producing it Galvanic Skin Response: Measures the conductivity of your skin Dilation of your sweat glands This device takes all this information, runs them through different equations and cross-references those equations

M ULTI - SENSORY D EVICE

I NFORMATION P ROVIDED

V ALIDITY AND R ELIABILITY SWA vs. Indirect Calorimetry(IC) Methods 26 subjects wearing SWA during resting conditions and Cycle-ergometer exercise Results Energy Expenditure Rest: r = 0.75 (strong) Exercise: slight underestimation of energy expenditure for active EE. Conclusion EE data from SWA highly correlated with data from gold standard IC SWA provides reasonably accurate measurements of free- living EE in individuals

V ALIDITY AND R ELIABILITY SWA vs. Doubly Labeled Water (DLW) Methods EE measured in 45 subjects via SWA and BLW over 10 days Results SWA = 117 kcal/day < DLW Correlation r = 0.81 (strong) Conclusion EE data from SWA highly correlated with data from the gold standard DLW

V ALIDITY AND R ELIABILITY

F EASIBILITY Help/BodyMedia-FIT-Feedback Remember, as Validity and Reliability increase the feasibility decreases. Cost: Device: $120 Software: $ 7/month Device + Software originally = ~$2,000

S UMMARY The BodyMedia SWA is a portable device with multiple sensors to collect physiological data from monitoring PA and EE in personal individuals or professional setting. Studies show that the SWA is a valid device from measuring EE, PA, intensity levels and sleep efficiency in most free- living situations.