The goal of this clinical trial is to compare the impact of restricted sleep on brain blood health in healthy men and women. The main question[s] it aims to answer are:

• Whether morning cerebral blood flow velocity is greater following a night of normal sleep compared to restricted sleep
• Whether the effect of sleep restriction on cerebral blood flow will be greater in males compared to females Participants will complete one 1-hour screening visit and two 2.5-hour study visits. Study visits will be conducted on two separate days.

Transcranial Doppler (TCD) is a non-invasive diagnostic tool used to estimate cerebral blood flow velocity (CBFV), cerebral autoregulation, cerebrovascular reactivity (CVR), intracranial pressure, cerebral perfusion pressure as well as other indicators of cerebral hemodynamics and autoregulation. Whereas TCD has been widely used in research, clinical, and outpatient settings, studies specifically designed to examine the effect of limited sleep on brain health and potential impact of sex are sparse. Thus, the present study will investigate sex-specific differences in cerebral blood flow under conditions of normal and restricted sleep. Investigators will conduct measures of CBFV and CVR on two separate days under tightly controlled experimental conditions. This study hypothesizes greater morning cerebral blood flow velocity following a night of normal sleep compared to restricted sleep. This study further hypothesize the effect of sleep restriction on CBFV and CVR will be greater in males compared to females. Results from the present study will provide important data necessary to develop future, well-controlled studies examining the impact of long-term modifications in exercise and/or sleep on cerebral hemodynamics and, by extension, risk for cerebrovascular events (i.e. stroke).

Inclusion Criteria:

• Healthy adult men and women, 18-45 years of age, BMI 18-30 kg/m2, non-pregnant, non-breastfeeding, and non-nicotine users

Exclusion Criteria:

• any medications known to affect sleep, autonomic, metabolic, or cardiovascular health, have a self-reported history of hepatic, renal, pulmonary, cardiovascular, or neurological disease, stroke or neurovascular disease, bleeding/clotting disorders, sleep apnea or other sleep disorders, diabetes, history of alcoholism or substance abuse, major cardiovascular event or surgical procedure within the past three months, or hypertension