Validity of three smartwatches in estimating energy expenditure during outdoor walking and running

Abstract

Commercially wrist-worn devices often present inaccurate estimations of energy expenditure (EE), with large between-device differences. We aimed to assess the validity of the Apple Watch Series 6 (AW), Garmin FENIX 6 (GF) and Huawei Watch GT 2e (HW) in estimating EE during outdoor walking and running. Twenty young normal-weight Chinese adults concurrently wore three index devices randomly positioned at both wrists during walking at 6 km/h and running at 10 km/h for 2 km on a 400- meter track. As a criterion, EE was assessed by indirect calorimetry (COSMED K5). For walking, EE from AW and GF was significantly higher than that obtained by the K5 (p < 0.001 and 0.002, respectively), but not for HW (p = 0.491). The mean absolute percentage error (MAPE) was 19.8% for AW, 32.0% for GF, and 9.9% for HW, respectively. The limits of agreement (LoA) were 44.1, 150.1 and 48.6 kcal for AW, GF, and HW respectively. The intraclass correlation coefficient (ICC) was 0.821, 0.216 and 0.760 for AW, GF, and HW, respectively. For running, EE from AW and GF were significantly higher than the K5 (p < 0.001 and 0.001, respectively), but not for HW (p = 0.946). The MAPE was 24.4%, 21.8% and 11.9% for AW, GF and HW, respectively. LoA were 62.8, 89.4 and 65.6 kcal for AW, GF and HW, respectively. The ICC was 0.741, 0.594, and 0.698 for AW, GF and HW, respectively. The results indicate that the tested smartwatches show a moderate validity in EE estimations for outdoor walking and running.

The Energy a Plastic Surgeon Expends during Liposuction

“…Therefore, we are confident of the reliability of the energy expenditure records obtained using the Apple Watch in this study. [5][6][7][8][9][10][11][12] Our research indicated that liposuction has the highest energy output among plastic surgeons. This physical activity requires covering 5.7 km in 31 minutes, representing an impressive and considerable effortfar exceeding any other type of operation-to obtain 4407 cm 3 of fat at a heart rate of 90 beats per minute.…”

“…Therefore, we are confident of the reliability of the energy expenditure records obtained using the Apple Watch in this study. 5–12…”

A contactless monitoring system for accurately predicting energy expenditure during treadmill walking based on an ensemble neural network

“… 12 , 16 , 32 However, these wearable devices exhibit errors ranging from 27% to 93% when evaluated using new subjects. 2 , 33 Furthermore, the overall correlation with indirect calorimetry was observed to be 0.34 for all monitors. 25 To improve prediction accuracy, researchers have studied new approaches involving machine learning (ML) and deep learning algorithms to develop regression models for monitoring walking EE.…”

Accuracy of the Huawei GT2 Smartwatch for measuring Physical Activity and Sleep among Adults during Daily Life: A Validation Study (Preprint)

“…Aligning with findings from other smartwatch research on TDAEE [38,[39][40][41][42], our results reveal that while the GT2 demonstrates moderate validity compared to the Actigraph, its in TDAEE measurements is still not ideal as shown by a high level of errors against Actigraph (MAPE>30%). Le et al [43] previously analyzed the GT2's EE accuracy against the Cosmed K5 in outdoor scenarios, reporting ICCs of .76 and .68, and MAPEs of 9.9% and 11.9% in walking (6 km/h, 2 km) and running (10 km/h, 2 km) scenarios, respectively. These findings generally agree with our results, underscoring the GT2's relative accuracy in energy expenditure measurement.…”

“…While the accuracy of smartwatches has been explored in previous research studies, research specifically focusing on their performance across different age groups in a free-living environment remains scarce, particularly within the Chinese population. The Huawei smartwatch ranks second in global sales in Q2 2023 and holds a high market share of 39% in China [57], but received limited empirical research attention on its accuracy [22,43], especially with regard to measurements of energy expenditure and sleep duration [38,53,58]. Considering its significant market prominence, it is crucial to rigorously assess the accuracy of the Huawei smartwatch in measuring health-related indices to ensure its validity for users' health monitoring and lifestyle management.…”