Energy Expenditure Responses to Acute Exercise in Older Women (Calorie Expenditure and Exercise)

Inclusion Criteria: 1. Women 2. Age 60-75 years 3. normal weight 4. Weight-stable (± 5%) within the previous 3 months 5. Non-smoking for last year 6. Able to provide own transportation to study visits 7. Not currently involved in any other research study 8. Willing and able to participate in all aspects of the trial including research testing 9. Willing to give informed consent to participate Exclusion Criteria: 1. Self-reported significant cardiovascular disease 2. Other self-reported medical conditions such as diabetes, chronic or recurrent respiratory conditions, active cancer, musculoskeletal disease 3. Medications known to affect exercise performance or metabolism 4. Excess caffeine use (\> 500mg/day) 5. Any self-reported contraindications to exercise 6. Clinical depression 7. Abnormal cognitive function -