Heat & Aerobic Training (HEAT) Study

Inclusion Criteria: * Age 45 to 64 * Confirmed pre-hypertensive (120-139 mmHG Systolic / 80-89 Diastolic mmHG) blood pressure by our laboratory staff * Low active (\< 2 days per week for 30+ minutes over the past 3 months) * Able and willing to try to adhere to American Heart Association guidelines for managing multiple lifestyle factors contributing to high blood pressure including increasing physical activity (at least 50 minutes, 3 times/week as part of our supervised training sessions), stopping smoking altogether, eating healthier (limiting sodium, eating fruit, veggies, low-fat dairy and lean protein, and reducing saturated fat and total fat), drinking less alcohol (1-2 drinks a day max) and achieving and maintaining a healthy bodyweight (striving or a body mass index between 18 and 25). * Able to commit to the full length of our program without missing more than 2 consecutive weeks * Capable of performing moderately intensive aerobic exercise * Willing to be randomized to one of two groups * Able to commute to and from fitness facility and UIUC campus * Own smartphone and have reliable at-home internet access * Have correctable vision (i.e., at least 20/40 with glasses or contacts with no color blindness) * Not involved in regular weekly relaxation methods (e.g., yoga, meditation) or heat therapy (e.g., steam-room, sauna, hot baths) * Not heat sensitive (e.g., have not experienced heat-induced severe rashes, pain, numbness, or tingling; experienced heat-related cramps, illness, or heatstroke; or had surgery requiring general anesthesia that has caused subsequent difficulty regulating body temperature) * Do not have any type of neuropathy (e.g., peripheral, diabetic) * Not depressed as indicated by a telephone screening (Abbreviated 5-item Geriatric Depression Scale; GDS-5 score \< 2) * No cognitive impairment as indicated by a telephone screening (Telephone Interview Cognitive Survey; TICS score \> 21) Exclusion Criteria: * Too young (\< 45) or too old (\> 64) * Normotensive (\< 120 mmHG Systolic / \< 80 Diastolic mmHG) or hypertensive (\> 140 mmHG Systolic / \> 90 Diastolic mmHG) blood pressure * Too active (as defined by regularly exercise 2 or more days per week for 30+ minutes over the past 3 months) * Unable or unwilling to comply with American Heart Association guidelines for managing multiple lifestyle factors contributing to high blood pressure including increasing physical activity (at least 50 minutes, 3 times/week as part of our supervised training sessions), stopping smoking altogether, eating healthier (limiting sodium, eating fruit, veggies, low-fat dairy and lean protein, and reducing saturated fat and total fat), drinking less alcohol (1-2 drinks a day max) and achieving and maintaining a healthy bodyweight (striving or a body mass index between 18 and 25). * Unable to commit to full length of program * Incapable of performing moderately intensive aerobic exercise * Unwilling to be randomized to one of two groups * Unable to commute to and from fitness facility and UIUC campus * Does not own smartphone or have reliable at-home internet access * Does not have correctable vision (i.e., at least 20/40 with glasses or contacts with no color blindness) * Already involved in regular weekly relaxation methods (e.g., yoga, meditation) or heat therapy (e.g., steam-room, sauna, hot baths) * Has heat sensitivity (e.g., heat-induced severe rashes, pain, numbness, or tingling; experienced heat-related cramps, illness, or heatstroke; or had surgery requiring general anesthesia that has caused subsequent difficulty regulating body temperature) * Has any type of neuropathy (e.g., peripheral, diabetic) * Has depression (as defined by GDS-5 score of 2 or higher) * Has cognitive impairment (as defined by \< 21 on TICS)