  Wearable electronics are often used for estimating the energy expenditure of
the user based on heart rate measurement. While heart rate is a good predictor
of calorie consumption at high intensities, it is less precise at low intensity
levels, which translates into inaccurate results when estimating daily net
energy expenditure. In this study, heart rate measurement was augmented with
heat flux measurement, a form of direct calorimetry. A physical exercise test
on a group of 15 people showed that heat flux measurement can significantly
improve the accuracy of calorie consumption estimates when used in conjunction
with heart rate information and vital background parameters of the user.
