Table 1.

Monitors’ technical characteristics

Monitor	Output	Size	Position	Technology
Monitor 1: Impedance	ECG, HR, BR, and PAL	7.5×5.0×2.0 cm, weight 60 g	Attached to the chest and upper abdomen	Electrode array (impedance)
Monitor 2: PPG	BR	56×36×62 mm, weight 54 g	Worn on the wrist with a finger probe	PPG
Monitor 3: Camera	BR and HR	N/A	Participant was videoed while in sitting position	Distance PPG algorithm
Monitor 4: Accel	BR and PAL	4.5×3.5×1.3 cm, weight 18 g	Attached to the upper abdomen just below the ribs and taped to the skin	Accelerometer
Monitor 5: Chest-band	HR, R-R Interval, BR, ECG, posture, PAL • Posture • Activity level • Peak Accel	2.8×0.7 cm, weight 89 g (including the chest strap)	Chest strap and an electronics module that attaches to the strap	Pressure sensor pad and accelerometer

Abbreviations: BR, breathing rate; ECG, electrocardiogram; HR, heart rate; PAL, physical activity level; PPG, photoplethysmography; N/A, not applicable; R-R, distance between 2 R peaks on ECG; Accel, accelerometer.