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Exercise and Sleeping Metabolism

The IMAGE Group and the Division of Geriatrics at the University of Colorado Anschutz Medical Campus are looking for healthy men and women aged 20 to 35 years, who have a BMI < 30, are sedentary to moderately active, and have a regular sleep schedule.

The goal of the study is to look at how a session of treadmill exercise performed during the day impacts your metabolism during the nocturnal period when sleep is occurring. The primary fuel source for the body during sleep is fat and there is evidence that daytime exercise enhances fat metabolism during sleep in men to a greater extent than in women. Why fat metabolism during sleep is different between men and women is not known. However, adults spend about one-third of the day sleeping, and understanding more about how men and women metabolize fat during sleep has implications for weight loss and the prevention of weight gain.

Healthy men and women (age range 20-35 years old) are eligible for this study. Participants should not be exercising more than 3 days/week and have a body mass index (BMI) of less than 30 kg/m2. You can check your BMI by entering your height and weight on the following website: NIH BMI Calculator. Participants should also have a habitual sleeping pattern of > 7 hours not to exceed 9.25 hours of sleep per night. If you are enrolled in this study you will complete a screening visit which involves measurements of your body composition and fitness. You will also complete two study phases (exercise phase and no-exercise phase) which involve 24 hour stays at the University of Colorado Hospital where the study team will measure your metabolism during the day and night. Meals will be provided to you for two days leading up to both study phases and during the hospital stays. Frequently Asked Questions:

  • What will I be paid for participating in this study?
    The compensation for finishing this study is $300.00. If the study is not completed for any reason, compensation is provided at $25 for the screening visit, $25 for the baseline measures, and $125 for each study phase completed.
  • Where do I go for study testing?
    All of our testing will be on the Anschutz Medical Campus (Fitzsimons Campus) in Aurora. Testing is typically done Monday through Friday, with options for weekend testing if necessary.
  • How long will I be in this study?
    Participating in the study should take approximately 2 months from the start of the screening process until the completion of the study.
  • What are the benefits I will receive from this study?
    The study will allow you to learn more about your current health including body composition, metabolic rate, fitness, energy requirements for weight maintenance, and the quality of your sleep. Information obtained from this study will help us to understand why there are sex-based differences in nocturnal fuel utilization in response to exercise, and how this could impact weight loss. This information will help us to design future studies to address some of the differences between males and females in weight gain and cardiovascular disease risk.

Corey Rynders, PhD, is the Principal Investigator of this study. This study is funded by grants from the Colorado Clinical and Translational Sciences Institute (CCTSI), University of Colorado Center for Women’s Health Research (CWHR), and Denver Health. It is approved by the Colorado Multiple Institutional Review Board (protocol #13-0359). If you are interested in participating in the study, please contact Corey Rynders at 720-848-6461 or