Abstract: An apparatus for energy expenditure estimation includes a heart rate sensor for producing a heart rate value indicative of a heart rate of an individual, a heat-flux sensor for producing a heat-flux value indicative of a heat-flux flowing through a measurement area on the skin of the individual, and a processing system communicatively connected to the heart rate sensor and the heat-flux sensor. The processing system is configured to produce an estimate of the energy expenditure based on the heart rate value and the heat-flux value. The use of the heat-flux value improves the accuracy of the estimation especially during low-intensity exercise and rest, when both heart rate and acceleration values often fail to provide information meaningful enough for energy expenditure estimation.

Abstract: An apparatus for energy expenditure estimation includes a heart rate sensor for producing a heart rate value indicative of a heart rate of an individual, a heat-flux sensor for producing a heat-flux value indicative of a heat-flux flowing through a measurement area on the skin of the individual, and a processing system communicatively connected to the heart rate sensor and the heat-flux sensor. The processing system is configured to produce an estimate of the energy expenditure based on the heart rate value and the heat-flux value. The use of the heat-flux value improves the accuracy of the estimation especially during low-intensity exercise and rest, when both heart rate and acceleration values often fail to provide information meaningful enough for energy expenditure estimation.

Abstract: An apparatus for producing information indicative of metabolic state of a metabolic energy system comprises a processing device for receiving a signal that is indicative of a heat-flux generated by the metabolic energy system. The processing device is configured to maintain model data expressing relative contributions of the phosphagen system, the glycolytic system, and the aerobic system to muscular energy production as functions of time during physical loading of the metabolic energy system. The processing device is configured to form estimates for the energy production of the phosphagen system, the energy production of the glycolytic system, and the energy production of the aerobic system as functions of time and based on the model data and the signal indicative of the heat-flux. The estimates can be indicative of the instant metabolic state, and they can be utilized in physical training, weight control, and detection of metabolism-related health issues.

Abstract: A method for manufacturing a gradient heat-flux sensor includes: depositing a semiconductor layer on a planar surface, removing material from the semiconductor layer so that mutually parallel semiconductor ridges having slanting sidewalls are formed, and filling gaps between adjacent ones of the semiconductor ridges so that metal-semiconductor contact junctions are formed on the slanting sidewalls of the semiconductor ridges. Due to the metal-semiconductor contact junctions on the slanting sidewalls, the semiconductor ridges and the gap-fillers constitute an anisotropic multilayer structure for forming electromotive force in a direction perpendicular to the semiconductor ridges and parallel with the planar surface in response to a heat-flux through the anisotropic multilayer structure in a direction perpendicular to the planar surface.

Abstract: A heat-flux sensor includes first and second pieces made of different materials and arranged to constitute a contact junction for generating electromotive force in response to a temperature difference between the first and second pieces. The heat-flux sensor includes a first electric conductor connected to the first piece and a second electric conductor connected to the second piece so that the electromotive force is detectable from between ends of the first and second electric conductors. The mass and the heat capacity of the second piece are significantly greater than those of the first piece so that a heat-flux across the contact junction causes a temperature difference between the first and second pieces but no significant temperature change in the second piece. Thus, the electromotive force caused by the temperature difference is indicative of the heat-flux.