Heat Therapy, Functional Capacity, and Vascular Health in Older Adults

To test the hypothesis that home-based leg heat therapy improves functional capacity, vascular function, and exercise hyperemia in older adults.

Inclusion Criteria:55 to 80 years of ageNo tobacco/nicotine use within preceding 6 months (e.g., cigarettes, chewing tobacco, nicotine gum or patches, and vapor smoking)Systolic blood pressure <140 mmHg; diastolic blood pressure <90 mmHgNormal 12-lead ECG (reviewed by a physician)Normal clinical results from a medical exam reviewed by a board-certified physician (e.g., General Health Questionnaire - see attached document)Body mass index (BMI) <35 unless athletic/muscular build; calculation = body weight (kg)/height (m2)Females Only: Post-menopausalExclusion Criteria:Not meeting the age criteriaBody mass index (BMI) >35 unless athletic/muscular build; calculation = body weight (kg)/height (m2)Use of tobacco or nicotine products within the last 6 months (tobacco cigarettes, chewing tobacco, nicotine patches or gum)Not abstaining from the following 24 hours prior to the experimental session: exercise, alcoholic substances, prescription or non-prescription medications (unless cleared by the medical screener), dietary supplements, herbal medications, caffeinated substances (including chocolate, coffee, tea (iced or hot), caffeinated energy drinks, and sodas)S who weigh less than 80 lbsUse of prescription drugs, non-prescription drugs or herbal medicines known to alter vascular function unless cleared prior to the studyUse of anti-hypertensive medicationsUse of beta blockersDaily use of bronchodilatorsCurrent use of anti-coagulant therapyCurrent use of hormone replacement therapy (e.g., estrogen, testosterone)Current diagnosis of cancerSigns of overt cardio-metabolic abnormalities (e.g., uncontrolled diabetes - HbA1c >7.5, a resting systolic blood pressure >140mmHg or diastolic blood pressure >90mmHg; abnormal 12-lead ECG)History of cerebrovascular abnormalities (e.g., prior stroke, transient ischemic attacks, epilepsy, increased intracranial pressure)Known history of atherosclerosis (i.e., plaque formation)Autonomic dysfunction (e.g., Shy-Drager Syndrome, Bradbury-Eggleston syndrome, idiopathic orthostatic hypotension)Respiratory illnesses (e.g., chronic asthma (including exercise-induced asthma), Chronic Obstructive Pulmonary Disease, Reactive Airway Disease). Note: subjects with exercised-induced asthma or who have had COVID-19 will be allowed to participateHistory of anaphylaxisSevere phobia of needlesHistory of alcohol or drug abuse which inhibits the participants ability to complete this studyLatex allergyKnown allergies or sensitivities to drugs used in the study (e.g., Lidocaine HCL, acetylcholine HCL, sodium nitroprusside, nitroglycerin, or related drugs)Implanted electronic medical devices (e.g. cardiac pacemaker)Tissue or skin abnormalities of the legs (e.g., infection, injury, open wound, ischemic tissue, phlebitis, active bleeding, neuropathy)Tissue or skin abnormalities of the arm (e.g., unhealed or open wound or circulatory deficits)Current Fever (oral temp >99.5 °F/ 37.5 °C) aa) Current use of PDE3 inhibitors (e.g., Viagra) or soluble guanylate cyclase (sGC) stimulators (e.g., riociguat), or unwillingness to withhold medication for 2 weeks prior to laboratory testing bb) Diagnosis of neurological disease or cognitive dysfunction cc) Cardiac surgery or cardiac events (e.g., coronary artery bypass graft surgery, myocardial infarction, heart failure) dd) Abnormal clotting, clots in deep veins in the legs or pelvis, or blood clots to the lungs ee) Individuals who have had mastectomies ff) History of methemoglobinemia