BODYMEDIA SENSEWEAR ARMBAND Physical Activity Monitor

MEASURING PHYSICAL ACTIVITY

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)

BODYMEDIA 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)

MULTI-SENSORY DEVICE

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

MULTI-SENSORY DEVICE

INFORMATION PROVIDED

INFORMATION PROVIDED

VALIDITY AND RELIABILITY

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

VALIDITY AND RELIABILITY

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

VALIDITY AND RELIABILITY

VALIDITY AND RELIABILITY

FEASIBILITY

http://www.bodymedia.com/Support-Help/BodyMedia-FIT-Feedback

Remember, as Validity and Reliability increase the feasibility decreases.

Cost: Device: $120 Software: $ 7/month Device + Software originally = ~$2,000

SUMMARY

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.