The investigators propose to test the hypothesis that a six-month intervention of combined fitness and cognitive training in the form of dancing will have a significant positive effect on a variety of executive control and memory processes as well as brain structure and function as compared to a non-aerobic strength and balance control/comparison group. Additionally, these two groups will be compared to walking groups in which one of the walking groups will also be provided with a daily, liquid, milk-based nutritional supplement.

Our previous trial (known as HALT, Healthy Active Lifestyle Trial) suggests that improvements in aerobic fitness have beneficial effects on cognitive function that are rather specific. That is, improvements in aerobic fitness appear to result in improvements in executive control processes such as scheduling, planning, coordination, inhibition, and working memory - some of the very cognitive abilities most affected during aging. Indeed, executive control processes and the prefrontal and frontal regions which support them have shown substantial and disproportionate age-related declines. The main hypothesis that the investigators test in the present project is that such deficits may be particularly benefited by improvements in aerobic fitness combined with cognitive training in the form of dance. Additionally, we will compare the outcomes of these interventions with an aerobic condition (walking) group and an aerobic condition (walking) group that also is provided with a daily nutritional supplement (walking + nutrition). The investigators will examine the relationship between aerobic fitness, physical activity, cognitive status, and brain function with this six-month aerobic training intervention study. The investigators will collect psychosocial data and functional fitness data to assess other relevant changes in psychological and physical function brought about by exercise training. Healthy, non-active older adults (60 to 79 years of age) will be recruited from the local community. Half One quarter of the older adults will be randomly assigned to an aerobic/cognitive combination group (dance), one quarter will be while the remaining half of the older adults will be randomly assigned to a non-aerobic control group (stretching, strengthening, and stability), one quarter will be assigned to the walking group, and one quarter will be assigned to the walking + nutrition group. The exercise interventions will be conducted by trained exercise staff. The participants will be assessed before and after the intervention (6 months). Assessments will include (a) cardiorespiratory testing, (b) physical activity monitoring (c) performance on neurocognitive tests of executive and non-executive function (d) measures of brain activation (fMRI) during cognitive tasks in a 3.0 tesla MRI system (e) a battery of psychosocial questionnaires (f) functional performance measures and (g) a mock street walking task.

Inclusion Criteria:

• 60-79 years of age
• Low-active: zero to two days of physical activity (> 30 minutes per day) per week in previous six months.
• Personal physician's examination and/or consent to participate in testing and exercise intervention
• Successful completion of graded exercise test without evidence of cardiac abnormalities or responses which are likely to be exacerbated by exercise. This decision will be made by the attending cardiologist.
• Adequate responses to the Telephone Interview of Cognitive Status (TICS-M) questionnaire
• Corrected (near and far) acuity of 20/40 or better in both eyes and no diagnosis of color-blindedness
• Initial depression score on GDS-15 (Geriatric Depression Scale) below clinical level (> 10)
• No presence of implanted devices or metallic bodies above the waist
• No history of brain surgery that involved removal of brain tissue
• Right-handed
• No history of stroke or Transient ischemic attack(TIA)
• Intention to remain in the local area for the duration of the intervention or testing period
• English fluency

Exclusion Criteria:

• Below 60 years of age or above 80 years of age at beginning of intervention
• Self-reported regular physical activity of more than 2 times per week in last six months
• Non-consent of physician
• Evidence of abnormal cardiac responses or conditions during graded exercise testing
• Inadequate responses to the Telephone Interview of Cognitive Status (TICS-M) questionnaire (<20)
• Uncorrectable (near and far) acuity of greater than 20/40 in either eye and/or color-blindness
• Depression score on GDS-15 indicative of clinical depression (≤ 10)
• Presence of any implanted devices above the waist i.e. cardiac pacemaker or auto-defibrillators; neural pacemaker; aneurysm clips in the Central Nervous System(CNS); cochlear implant; metallic bodies in the eye or CNS; any form of wires or metal devices that may concentrate radiofrequency fields
• History of brain surgery that involved removal of brain tissue
• Left-handed
• History of Stroke or TIA
• Intent to move or be away from the area for an extended period of time (i.e. > 3 weeks) during the intervention or testing period
• Inability to communicate effectively in English