| HR | Heart Rate |
| HRV | Heart Rate Variability |
| bpm | beats per minute |
| ECG | electrocardiogram |
| FB | Fitbit Charge |
| AW | Apple Watch |
| TT | Tomtom Runner Cardio |
| G2 | Samsung G2 |
| LED | light emitting diode |
| PPG | photoplethysmogram |
| accuracy root-mean-square | |
| APE | absolute percent error |
| ICC | interclass correlation coefficient |
| SD | standard deviation |
| R | Spearman’s rank correlation |
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