Sensing leg movement enhances wearable monitoring of energy expenditure

Physical inactivity is a major global health concern. While methods like respirometry and doubly labeled water accurately measure energy expenditure, they are impractical for everyday use. Smartwatches offer portability but suffer from significant errors. This paper introduces a Wearable System that estimates metabolic energy expenditure in real-time during various activities with substantially lower error than existing methods. Using inertial measurement units on the shank and thigh, the system distinguishes lower-limb activity more effectively, leading to a cumulative error of 13% across common activities – significantly lower than the 42% error observed with a standard smartwatch and 44% with an activity-specific smartwatch. This accurate monitoring enables new possibilities for energy balance systems in weight management and large-scale activity tracking.

Patrick Slade, Mykel J. Kochenderfer, Scott L. Delp, Steven H. Collins