Inclusion Criteria:  Age 65-85 years Gender: Men or Women MOCA > 26 Independently living and able to drive OSA (AHI ≥ 15/h) or no OSA Subjects must consent to waiving their right to obtain their PHS score (since the score is not yet actionable and could lead to social stress and ethical dilemmas)  Exclusion Criteria:  Currently smoking History of COPD or asthma Heart Failure Class III or IV, unstable cardiovascular disease, or uncontrolled hypertension Neuromuscular Disease Drowsy Driving (ESS > 18/24) Inability to complete study procedures, such as questionnaire that are only available/validated in English Lack of decisional capacity to provide informed consent Participants in whom magnetic resonance imaging Magnetic Resonance Imaging [MRI] is contraindicated including, but not limited to, those with a pacemaker, presence of metallic fragments near the eyes or spinal cord, or cochlear implant Presence of a brain tumor or lobar stroke Current drug or alcohol abuse/dependence Prisoners