Human centric lighting (HCL) is a technology that supports the body's circadian rhythm, as it can stimulate the sleep triggering hormone, melatonin, to improve sleep hygiene over standard lighting (SL), and promote recuperative sleep for a timely return-to-duty. In intensive care units, exposure to HCL has improved sleep measures. However, the effect in the medical surgical (MS) environment is unknown. The purpose of this study is to assess the feasibility of study procedures in MS setting and conduct a preliminary evaluation of the effect of light on inpatient sleep. Recruitment started November 2020 through April 2021. Data analysis is pending.

Inclusion Criteria:

• Patient who is an active duty service member, GS Civilian, Dependent or Retiree affiliated with the Army, Air Force or Navy.
• Patient who is informed by provider or anticipates being admitted for at least two nights.
• Patient who can read and speak English fluently (since surveys are not translated in any other language).

Exclusion Criteria:

• Patient with visual impairment which cannot be corrected with glasses or contact lenses such as complete blindness, (defined as inability to see light), or partial blindness (defined as very limited vision) such as patients with history of cataracts.
• Patient taking an oral medication for sleep.
• Patient receiving radioactive ionization treatment.
• Patient who requires isolation or palliative care.
• Patient recovering from head/neck or oral maxillofacial surgery that would impede saliva sample collection (i.e. jaw wiring, extensive gauze packing in oral cavity)
• Patient who reports status as a Department of Defense Contractor at screening.