Guided Episodic Future Thinking to Increase Physical Activity Adherence and Promote Healthy Brain Aging

Inclusion Criteria: * speak English * have access to reliable communication (a telephone or cell phone, computer, etc.) * normal or corrected to normal vision and hearing * ambulatory (without the use of assistive devices) * physically underactive * able to give informed consent * able to exercise continuously on the recumbent stepper exercise device for 4 minutes greater than or equal to 25 watts to demonstrate ability to perform exercise on stepper \& no aerobic exercise contraindications or other safety/physical concerns * able to communicate with investigators, follow 2-step command \& correctly answer consent comprehension questions * stable blood pressure and statin medication doses for 30 days as these affect vascular health/hemodynamics * willing and able to safely enter magnetic resonance (MR) scanner and attempt the MR scan * willing and able to attempt a blood draw Exclusion Criteria: * patients with arrhythmias or acute cardiac events will be excluded due to potential complications with the supervised moderate exercise * at risk for hazard due to magnetic fields due to MR safety concerns * have any neurologic or psychiatric disorder except depression, anxiety (including post-traumatic stress disorder) * have history of seizures or head trauma due to MR data quality