Actiheart Energy Expenditure
Advanced PAEE Monitoring
The Actiheart is a compact, chest-worn device that records ECG and tri-axial acceleration in a single, light-weight, waterproof unit and uses advanced branched modelling to combine both Heart Rate and Activity to provide accurate Activity Energy Expenditure (AEE) in free living. The Actiheart has hundreds of peer reviewed publications from leading researchers around the world.
How does it work?
The Actiheart records activity and derives heart rate from ECG and uses both parameters to calculate Activity Energy Expenditure (AEE). By combining both activity and heart rate, the accuracy of the energy expenditure calculation is substantially improved over using just activity or just heart rate alone. Energy Expenditure calculations are within 0.02kJ/kg/min of those measured by a Cosmed K4b23.
The Actiheart has been validated against Doubly Labelled Water for measuring AEE and is the acknowledged standard for ambulatory AEE measurement.
Details of the system of branched modelling used in the Actiheart are shown below.
Energy Models and Calibration
The Actiheart software incorporates a range of pre-configured energy expenditure models which offer group calibrations for adults or children in addition to the options to add individual calibration data for HR or activity. The default group models are based upon validation studies performed with the Actiheart and are recommended for use with the appropriate cohorts where individual calibration data are impractical or unavailable. The energy models are applied to both the Daily and Advanced Energy Expenditure modules.
Key Terms:
| REE: | Resting Energy Expenditure (derived from Schofield Equations or an entered measured value) |
| AEE: | Activity Energy Expenditure (calculated using the branched model equations) |
| DIT: | Dietary Induced Thermogenesis (factored in as a constant of 10% of TEE) |
| TEE: | Total Energy Expenditure (REE + AEE + DIT) |
| PAL: | Physical Activity Level (TEE/REE) |
Daily Energy Expenditure
The focus of the Daily Energy Expenditure analysis is to provide a simplified display with minimal options to allow a rapid determination of daily TEE. The main display window provides graphical indication for each day by means of a stacked bar graph in addition to daily numerical values for AEE, DIT, TEE and PAL. There are options for reporting and multiple data export options built in to the analysis window.
Advanced Energy Expenditure
Designed for more flexible measurement of Energy Expenditure and including many more options for individual calibration adjustment and breakdown of the branched model. Makes use of heart rate and activity data in IBI mode with the Actiheart 5.
The main display window provides daily graphical view of HR and activity with a separate graph of energy expenditure which may be set to your preferred AEE measure/units. Any period of interest may be selected by highlighting the graph with further analysis utilities provided. There are options for reporting and multiple data export options built in to the analysis window.
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