Validation of a novel multi-sensor wearable for measuring heart rate, steps, and energy expenditure in laboratory and simulated free-living protocols.

Objective.To evaluate the criterion validity of a new wearable device (DOFIT PRO) for heart rate (HR), step count, and energy expenditure (EE), and to compare accuracy across four wrist placements in laboratory and simulated free-living protocols.Approach.Thirty-two healthy adults wore four devices (right/left; proximal/distal) during a treadmill protocol (rest, 3.2 and 6.4 km h-1walking, 9.7 km h-1jogging, recovery) and ten standardized simulated free-living protocols. Criterion measures were chest-strap HR, video-verified steps, and indirect calorimetry (laboratory EE) and ActiGraph accelerometry (simulated free-living EE). Agreement was assessed using mean difference and mean absolute percentage error (MAPE).Main results.HR MAPE was excellent at rest/recovery (0.61%-5.18%) but deteriorated during brisk walking (20.69%-27.63%) and jogging (32.96%-41.77%), with substantial underestimation. Step-count accuracy was excellent-good for walking (1.94%-7.30%) and good-acceptable for stair climbing (6.05%-11.66%), but running showed strong placement effects (treadmill jogging MAPE: right wrist 38.84%-50.35% vs left wrist 7.97%-13.47%). Arm-dominant tasks produced marked step overestimation (e.g. shopping MAPE 83%-95%). EE showed the lowest validity overall, with the most consistent performance during simulated free-living protocols (MAPE 6.98%-10.93%) and improved accuracy on the left wrist during vigorous tasks.Significance.DOFIT PRO appears suitable for resting HR monitoring and step-based assessment of locomotor activity in controlled contexts, whereas vigorous-exercise HR and EE estimates should be interpreted cautiously with attention to activity type and wear location. These findings align with broader evidence that wearable validity is activity- and context-dependent and support the need for device- and placement-specific validation.