Techniques for measuring energy expenditure with portable devices

In this paper we present a summary of the techniques that can be used for measuring energy expenditure (EE) with particular emphasis on those techniques that are best suited for integration in portable monitoring devices. We discuss the pros and cons of the various measurement techniques and present experimental results that show that the most popular technique for monitoring EE (using an accelerometer) is prone to significant errors. We discuss the need for a modular device that balances the desire for accurate measurements with comfort and power consumption and derive design parameters for such a device. We also give some preliminary results from a modular, portable EE monitoring device that is being developed in light of this discussion.