Personal Metabolic Fuel Sensor.

The advent of miniature low power sensors for gas concentration, temperature, humidity, and volumetric flow rate measurement has enabled the development of a metabolic fuel and energy sensor which is sufficiently small in size, easy to use, and low cost to support personal ownership for on-demand metabolic measurement and tracking. The sensor is $\sim 100\text{X}$ smaller than conventional metabolic carts and utilizes a novel passive proportional valveless breath sampling architecture to support on-demand measurement of fuel substrate utilization and energy expenditure over the full range of activity from rest to intense exercise. The sensor functions over the full range of humidity and temperatures above freezing, and does not require consumables. The accuracy and measurement range are demonstrated by means of a controlled mechanical breathing simulator and independently validated in a human subject study which compared the sensor measurements to a gold-standard clinical metabolic cart. [ABSTRACT FROM AUTHOR]