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

The proposed project will target regulation and reward systems using guided imagery to increase exercise adherence by increasing positive affect and the evaluation of future rewards among mid-life adults. The investigators will conduct a within subject design in 160 mid-life adults (45-65 years of age) and examine the impact of different components of guided imagery on exercise adherence, regulation systems indexed by delay discounting, positive affect related to exercise, and functional neuroimaging (i.e., connectivity between regulation and reward brain regions). Participants will be asked to complete three assessment appointment periods: 1) baseline, 2) 6-weeks (i.e., end of exercise intervention), and 3) 12-weeks. Each appointment will include assessment of primary outcome measures of delay discounting and exercise positive affect. In addition, baseline and 6-week appointments will include functional magnetic resonance imaging (fMRI) assessments of functional connectivity between reward and regulation regions. Physical activity will be measured at baseline, immediately following the intervention, and 6 weeks following the intervention to explore changes in physical activity across study participation. At the end of the final appointment participants will be debriefed on the goals of the study and asked to provide feedback related to feasibility, the guided imagery experience, and exercise intervention experience to inform future research. In addition, blood draws will be completed at baseline to assess genetic risk for developing Alzheimer's disease (i.e., APOE). If successful, this approach could be used in future studies to increase participation in exercise and adherence to exercise interventions with the goal of promoting brain health and reducing the risk of developing Alzheimer's disease. The design of the proposed clinical trial permits a rigorous evaluation of the role of engaging regulation and reward systems to change immediate and future reward. The exercise intervention will consist of one-on-one high intensity interval training (HIIT) overseen by an exercise specialist twice a week for 6 weeks. Exercise adherence will be monitored as the percentage of the weekly exercise and adherence to the HIIT protocol.

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