Physiological and neurocognitive changes experienced as a result of increasing age may influence socioemotional functioning and economic behaviors, yet, the mechanisms through which these changes occur are not well understood. Studies have also shown that aerobic exercise may protect against age-related cognitive decline in other domains. This research is designed to test the hypothesis that aerobic exercise will enhance social, emotional and economic functioning in older adults, and that these effects will occur via the effect of exercise on neurocognitive structure and function assessed via magnetic resonance imaging (MRI). Advancing our knowledge of the mechanisms that influence emotional, social and economic functioning could inform the development of targeted treatments and prevention programs for older adults.

Inclusion Criteria:

• Age 25-35 for younger adults, and age 60 or over for older adults
• Sedentary (i.e., < 60 minutes per week of moderate physical activity in the past 6-months)
• Able to make fewer than 3 errors on the Pfeiffer Mental Status192
• Willing to accept random assignment to condition (older adults)
• Physically capable of safely engaging in moderate exercise activity (i.e., no injuries, physical impairments, or pre-existing contraindications) as assessed by a study physician
• Able to successfully complete a maximal exercise test without evidence of cardiac or other abnormalities
• Planning to remain in the Boulder-Denver metro area for the next 4 months (older adults)

Exclusion Criteria:

• Are a heavy smoker (>20 pack years)
• Are diabetic
• Have a body size exceeding the capacity of the magnetic resonance imaging machine (approximately 23" in diameter)
• Are on antipsychotic medications
• Are currently under treatment for any psychiatric disorder, including clinical depression, Alzheimer's, or dementia
• Are currently pregnant
• Have magnetic resonance imaging contraindications (i.e., non-removable metallic implants, claustrophobia, traumatic brain injury, current pregnancy, etc.)