Healthy sample
Inclusion Criteria:
* Ages 18-85 y
* Body mass index (BMI) \<30 kg/m2
* Self-reported habitual sleep duration of 6-9 hours
* Willing and able to comply with the study requirements
Exclusion Criteria:
* High risk for mild-to-severe sleep apnea
* Individuals with pacemakers
* Non-English speakers
* Individuals who are unwilling or unable to provide informed consent or comply with study procedures
* Current active illness (e.g., cold, flu, bronchitis, suspected COVID-19)
* Have known allergies or previous reaction to titanium or medical-grade plastic
* Report regularly sleeping \<4 hours per night
* Restricted peripheral circulation (e.g. Raynaud's disease)
* Individuals with physical limitations or deformities or skin conditions that would preclude safely wearing up to two Oura Ring devices or reference polysomnography equipment
* Individuals that have completed overnight rotating shift-work in the past 2 weeks
* Individuals that have traveled across time-zones in the past week
* Current use (within the past month) of the following medications/classes, pending investigator decision: Stimulants (Adderall, Ritalin); Sodium oxybate; Heroin, cocaine, or methamphetamines; Non-stimulant wake promoting agents (e.g. modafinil, pitolisant, etc.); Prescription sleep medication
* Individuals employed by a company that develops or sells medical and/or fitness devices in a similar space (e.g. wearables) or are technology journalists (e.g. professional bloggers, TV, magazine, newspaper reporters, etc.)
Sleep Apnea sample Inclusion Criteria
* High risk for mild-to-severe sleep apnea, defined by at least one of the following:
* Prior clinical diagnosis of obstructive sleep apnea (OSA)
* Currently seeking or actively undergoing treatment for sleep apnea (e.g., PAP therapy, oral appliance)
* Documented apnea-hypopnea index (AHI) ≥5 events/hour from a previous sleep study
* Self-reported Habitual sleep duration of 6-9 hours
* Willing and able to comply with study requirements Exclusion criteria
* Same as for Healthy Adult sample, with the exception of the "high risk for mild-to-moderate sleep apnea) criterion
