TABLE 1.

Features of the wearable devices to acquire physiological signals during a study session.

Device	Sampling rate	Sensor type	Variable measured	On-body location	Data collection application
Apple Watch Series 6	Variable, approximately once every 5-6 s using Workout App	Optical	HR	Wrist non-dominant hand	Apple Health
Empatica E4	1 Hz	Optical	HR	Wrist dominant hand	Empatica E4 Manager
Polar Verity Sense	1 Hz	Optical	HR	Upper arm non-dominant hand	Polar Flow
Polar H10	1 Hz	ECG	HRV	Chest	Elite HRV
Dreem 3	250 Hz	EEG	EEG	Head	Alfin

*Note: HR – Heart Rate, HRV – Heart Rate Variability, ECG – Electrocardiogram, EEG – Electroencephalogram.