The treatment of high blood pressure, or hypertension, is multifaceted and can include pharmacological therapies (i.e., medications) and lifestyle modifications such as physical activity. Chronotherapy, which describes timing of a treatment with the body's daily rhythms, has recently been used with hypertension medications and has been shown to be effective at lowering blood pressure and reducing the risk of cardiovascular disease events. Specifically, taking medications in the evening was shown to be more effective than morning medication routines. Little information is available about the effectiveness of chronotherapy combined with exercise (i.e., planned physical activity) interventions in older adults with hypertension. The purpose of this study is to examine how exercise training performed in the morning and early evening affects blood pressure and other measures of blood vessel health in postmenopausal females with hypertension.

Blood pressure has an internal rhythm associated with the 24-hr clock. Nocturnal blood pressure (BP) is a key contributor to cardiovascular health and may be improved by exercise. Moreover, the time of day of the exercise may be a key factor. This study aims to evaluate the effects of morning and evening exercise training on BP and other measures of vascular function in older females with hypertension.

Inclusion Criteria:

• Systolic BP equal to or greater than 130 mmHg without BP medication or greater than 120 mmHg with medication and diastolic blood pressure equal to and greater than 80 mmHg
• 55-80 years old
• Post-menopausal female
• Able to walk without assistance

Exclusion Criteria:

• Habitually physically active defined as 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic physical activity per week
• Overt pulmonary disease/condition as follows: chronic bronchitis, chronic obstructive pulmonary disease, emphysema, or pulmonary hypertension
• Cardiometabolic disease/condition as follows: diabetes, heart failure, peripheral arterial disease, stroke, coronary artery disease, renal disease, secondary hypertension, chronic venous insufficiency or deep vein thrombosis within last 6 months
• Cancer within last 5 years
• Body mass index >39 kg/m2
• Current smoking or vape
• Evening shift work
• uncontrolled thyroid disorder
• 2 or more falls in the last year
• Anemia within 3 months of enrollment
• Parkinson's disease
• Dementia
• Unstable angina
• Acute pulmonary embolus or infarction
• Acute myocarditis or pericarditis
• Acute aortic dissection