1.2.2. Procedure

After the clinical/adaptation PSG night, participants underwent another PSG night during which data from the FitbitChargeHR™ were concurrently collected.

Participants slept in sound-attenuated, temperature-controlled bedrooms in the sleep laboratory at SRI International. Lights-out and lights-on times were selected by participants. A breath alcohol test (S75 Pro, BACtrack Breathalyzers, San Francisco, CA, USA) and urine drug test (10 Panel iCup drug test kit, Instant Technologies, Inc.) were administered in the evening before each PSG night to ensure that none of the participants had recently used alcohol or drugs.