Table 2.
Analysis of the validity of energy expenditure measurements by wrist-worn wearables while sitting and walking/running at different intensities.
| Level of activity (METsa), intensity | Apple Watch Series 4 | Polar Vantage V | Garmin Fenix 5 | Fitbit Versa | |
| Inactive (1.3), sitting |
|
|
|
|
|
|
|
Energy expenditure (kcal/5 min)b, mean (SD) | 7.6 (1.6) | |||
|
|
Standardized mean bias | 2.59 (2.25 to 2.94) | 0.25 (–0.40 to 0.90) | 1.74 (0.77 to 2.71) | –0.72 (–1.46 to 0.02) |
|
|
Pearson’s r | 0.46 (0.16 to 0.68) | 0.41 (0.10 to 0.65) | 0.23 (–0.15 to 0.55) | 0.52 (0.16 to 0.76) |
|
|
Interpretation of Pearson’s r | Very poor | - | - | Very poor |
|
|
CVc (%) | 26.6 (21.2-36.2) | 28.0 (22.2-38.4) | 20.9 (16.3-29.7) | 17.1 (13.2-24.7) |
|
|
sTEEd | 1.84 (1.02-5.64) | 1.33 (0.79-2.94) | 4.24 (1.51-6.46) | 1.65 (0.87-6.09) |
|
|
Interpretation of sTEE | Very large | Very large | Extremely large | Very large |
| Light (3.5), 1.1 m/s |
|
|
|
|
|
|
|
Energy expenditure (kcal/5 min)b, mean (SD) | 20.6 (4.1) | |||
|
|
Standardized mean bias | 2.63 (2.23 to 2.03 | 1.29 (0.87 to 1.72) | –0.05 (–0.84 to 0.74) | 4.16 (3.97 to 4.36) |
|
|
Pearson’s r | 0.71 (0.49 to 0.85) | 0.67 (0.44 to 0.82) | 0.20 (–0.19 to 0.54) | 0.88 (0.76 to 0.94) |
|
|
Interpretation of Pearson’s r | Poor | Very poor | - | Good |
|
|
CV (%) | 15.1 (12.0-20.5) | 16.3 (13.1-22.1) | 16.8 (13.1-24.0) | 8.0 (6.3-11.2) |
|
|
sTEE | 0.99 (0.63-1.77) | 1.10 (0.70-2.03) | 4.86 (1.56-5.11) | 0.53 (0.35-0.85) |
|
|
Interpretation of sTEE | Large | Very large | Extremely large | Moderate |
| Vigorous (6.6), 1.9 m/s |
|
|
|
|
|
|
|
Energy expenditure (kcal/5 min)b, mean (SD) | 38.3 (6.5) | |||
|
|
Standardized mean bias | 1.58 (1.27 to 1.90) | 0.27 (–0.18 to 0.71) | –1.15 (–2.01 to –0.29) | 0.88 (0.56 to 1.20) |
|
|
Pearson’s r | 0.71 (0.49 to 0.84) | 0.49 (0.18 to 0.7) | 0.21 (–0.21 to 0.56) | 0.78 (0.57 to 0.89) |
|
|
Interpretation of Pearson’s r | Poor | Very poor | - | Poor |
|
|
CV (%) | 13.5 (10.8-18.1) | 17.1 (13.7-23.1) | 15.9 (12.2-23.3) | 11.2 (8.8-15.7) |
|
|
sTEE | 0.99 (0.64-1.76) | 0.65 (0.43-1.02) | 4.62 (1.46-4.73) | 0.81 (0.51-1.44) |
|
|
Interpretation of sTEE | Large | Large | Extremely large | Large |
| Vigorous (9.9), 2.7 m/s |
|
|
|
|
|
|
|
Energy expenditure (kcal/5 min)b, mean (SD) | 57.8 (11.0) | |||
|
|
Standardized mean bias | 0.79 (0.56 to 1.02) | –0.09 (–0.39 to 0.2) | –0.04 (–0.45 to 0.37) | –0.06 (–0.44 to 0.32) |
|
|
Pearson’s r | 0.80 (0.62 to 0.90) | 0.72 (0.51 to 0.85) | 0.57 (0.25 to 0.78) | 0.74 (0.51 to 0.87) |
|
|
Interpretation of Pearson’s r | Poor | Poor | Very poor | Poor |
|
|
CV (%) | 19.0 (15.1-26.2) | 21.9 (17.5-29.8) | 17.1 (13.3-24.4) | 14.1 (11-19.8) |
|
|
sTEE | 0.76 (0.50-1.25) | 0.97 (0.62-1.68) | 1.43 (0.80-3.91) | 0.90 (0.50-1.67) |
|
|
Interpretation of sTEE | Large | Large | Very large | Large |
| Vigorous (10.4), 3.6 m/s |
|
|
|
|
|
|
|
Energy expenditure (kcal/5 min)b, mean (SD) | 60.5 (26.7) | |||
|
|
Standardized mean bias | 0.32 (0.19 to 0.45) | –0.05 (–0.18 to 0.08) | 0.19 (–0.10 to 0.48) | –0.06 (–0.37 to 0.24) |
|
|
Pearson’s r | 0.95 (0.89 to 0.97) | 0.95 (0.89 to 0.97) | 0.84 (0.68 to 0.92) | 0.76 (0.52 to 0.88) |
|
|
Interpretation of Pearson’s r | Very good | Very good | Poor | Poor |
|
|
CV (%) | 20.3 (16.0-28.3) | 20.7 (16.4-28.6) | 34.5 (26.4-50.8) | 32.3 (24.6-48) |
|
|
sTEE | 0.34 (0.23-0.50) | 0.34 (0.24-0.51) | 0.64 (0.41-1.09) | 0.87 (0.53-1.65) |
|
|
Interpretation of sTEE | Moderate | Moderate | Large | Large |
| Vigorous (13.3), 4.1 m/s |
|
|
|
|
|
|
|
Energy expenditure (kcal/5 min)b, mean (SD) | 77.8 (46.6) | |||
|
|
Standardized mean bias | 0.34 (0.13 to 0.54) | –0.11 (–0.28 to 0.05) | 0.25 (–0.06 to 0.55) | 0.13 (–0.09 to 0.34) |
|
|
Pearson’s r | 0.93 (0.82 to 0.98) | 0.95 (0.87 to 0.98) | 0.91 (0.78 to 0.96) | 0.92 (0.81 to 0.97) |
|
|
Interpretation of Pearson’s r | Good | Very good | Good | Good |
|
|
CV (%) | 27.1 (19.6-45.1) | 22.7 (16.5-37.3) | 33.1 (24.3-52.9) | 29.9 (21.8-48.6) |
|
|
sTEE | 0.39 (0.23-0.71) | 0.32 (0.19-0.57) | 0.46 (0.28-0.80) | 0.41 (0.24-0.72) |
|
|
Interpretation of sTEE | Moderate | Moderate | Moderate | Moderate |
| Vigorous (13.8), intermittent sprints |
|
|
|||
|
|
Energy expenditure (kcal/5 min)b, mean (SD) | 80.4 (15.6) | |||
|
|
Standardized mean bias | 1.83 (1.52 to 2.13) | 0.23 (0.04 to 0.42) | –0.82 (–1.78 to 0.14) | –1.25 (–1.83 to –0.67) |
|
|
Pearson’s r | 0.66 (0.41 to 0.81) | 0.85 (0.72 to 0.92) | 0.21 (–0.19 to 0.56) | 0.42 (0.06 to 0.68) |
|
|
Interpretation of Pearson’s r | Very poor | Good | - | - |
|
|
CV (%) | 25.4 (20.2-34.7) | 17.5 (14.0-23.6) | 17.9 (13.8-25.9) | 20.8 (16.2-29.6) |
|
|
sTEE | 1.15 (0.72-2.19) | 0.63 (0.43-0.97) | 4.62 (1.50-5.05) | 1.64 (0.88-5.57) |
|
|
Interpretation of sTEE | Very large | Large | Extremely large | Very large |
| Vigorous (8.8), average of the values at all different intensities |
|
|
|
||
|
|
Energy expenditure (kcal/5 min)b, mean | 49.0 | |||
|
|
Standardized mean bias | 1.44 | 0.26 | 0.02 | 0.44 |
|
|
Pearson’s r | 0.75 | 0.72 | 0.45 | 0.72 |
|
|
Interpretation of Pearson’s r | Poor | Poor | Very poor | Poor |
|
|
CV (%) | 21.0 | 20.6 | 22.3 | 19.1 |
|
|
sTEE | 0.92 | 0.76 | 2.98 | 0.97 |
|
|
Interpretation of sTEE | Large | Large | Extremely large | Large |
aMETs: metabolic equivalents.
bMeasured according to the criterion measure.
cCV: coefficient of variation.
dsTEE: standardized typical error of the estimate.