Mechanisms of Impaired Brain Blood Flow With Aging

Exclusion Criteria

• •Pregnancy or breastfeeding;
• •Blood chemistries indicative of abnormal renal, liver, thyroid and adrenal function (i.e., outside of normal reference range); estimated glomerular filtration rate using the MDRD prediction equation must be \>60 ml/min/1.73 m2;
• •Abnormal blood chemistry that is clinically relevant or any blood chemistry marker that is +/-2.5x the upper or lower limit;
• •Lack of a suitable temporal window for cerebrovascular assessments;
• •Current smoking;
• •Chronic clinical diseases (e.g., coronary artery, peripheral artery, or cerebrovascular diseases, diabetes, chronic kidney disease, COPD);
• •Major psychiatric disorder (e.g. Alzheimer's disease or other form of dementia, schizophrenia, bipolar disorder, major depression within past two years);
• •Neurological or autoimmune conditions affecting cognition (e.g. Parkinson's disease, epilepsy, multiple sclerosis, head trauma with loss of consciousness greater than 30 min, large vessel infarct);
• •Current medication use likely to affect CNS functions (e.g. long active benzodiazepines);
• •Having past or present alcohol dependence or abuse, as defined by the American Psychiatry Association, Diagnostic and Statistical Manual of Mental Disorders;
• •Body mass index (BMI) \>40 kg/m2 (FMD measurements can be inaccurate in severely obese patients).