The purpose of this study was to determine the validity of the SenseWear HR Armband in measuring heart rate and energy expenditure. The SenseWear HR Armband was compared to an electrocardiogram (ECG), the Actiheart Mini Mitter and the Polar Heart Rate Monitor. Energy expenditure estimations were compared to indirect calorimetry (Cosmed\u27s K4 b2) measurement and the Actiheart Mini Mitter\u27s estimations. Thirty healthy adults (18-59 years old) participated in the study. The protocol consisted of 5-minute stages, starting with two resting stages (sitting and standing), followed by four walking stages (1.5, 2.0, 2.5 and 3.0 mph) and ending with a standing recovery stage. The SenseWear HR Armband consistently recorded higher heart rate when (2-8 bpm) compared to the ECG, the Actiheart Mini Mitter (1-3 bpm) and the Polar Heart Rate Monitor (4-8 bpm). The SenseWear Armband overestimated energy expenditure by approximately 0.5-1.0 kcal/min during the exercise stages of the protocol when compared to the indirect calorimetry measurements, while the Actiheart Mini Mitter consistently underestimated (0.5kcal.min) energy expenditure. The SenseWear HR Armband was found to be a valid device for measuring heart rate however, it consistently overestimated energy expenditure by about 10 during the exercise stages of the protoco
