Exploratory Study of Intermittent Hypoxia Treatment in Chronic Cerebral Hypoperfusion

Inclusion Criteria: * Subjects aged 45-70 years, BMI 18.5-24kg/m2, both sexes. * Subjects with risk factors of cerebrovascular disease, such as hypertension, diabetes, dyslipidemia, and so on, and the risk factors are well controlled. * Cerebral/carotid ultrasound showed mild stenosis of unilateral internal carotid artery (ICA) or middle cerebral artery (MCA) (\<50%) without stenosis of other major feeding arteries. * Subjects with the manifestations of chronic cerebral hypoperfusion, such as dizziness, head pain, memory loss, slow reaction, inattention, emotional instability, decreased ability to work, sleep disorders and mood disorders, the course of more than 3 months. * Subjects or their legally authorized representative can provide informed consent. Exclusion Criteria: * Stroke onset in the past 3 months, other severe neurological diseases, such as epilepsy, intracranial infectious diseases or demyelination. * Uncontrolled hypertension (systolic blood pressure ≥200mmHg) with antihypertensive drugs before enrollment, other cardiovascular diseases. * History of pulmonary, hepatic, dermatologic, or hematologic diseases. * History of substance abuse. * Pregnancy, hypertension, diabetes mellitus, obesity, sleep apnea and neurological disorders.