Exercise, Sleep Quality and Nocturnal Fat Oxidation in Metabolic Syndrome (ExerciZzz)

The Effect of Exercise on Sleep Quality and Nocturnal Fat Oxidation in Individuals With Metabolic Syndrome

Personnel resources required to conduct study are no longer available. Study was terminated due to lack of resources

The purpose of the Exerci-Zzz Study is to learn more about how the time of day that exercise is performed influences sleep quality and fat metabolism overnight in adults with metabolic syndrome. In this study, exercise will be performed in the early evening and the investigators will measure participants' sleep quality and fat metabolism overnight in a metabolic room. The total study will take approximately 2-3 months to complete. Enrolled participants will complete 2 study conditions (evening exercise and control) in a metabolic room. Each of these visits will last 30 hours and require that the participant stay in the metabolic room. During the evening exercise participants will be asked to perform exercise in the early evening. Finally, during the control condition participants will be asked spend the day in the metabolic room (no exercise performed during this condition). During each of these conditions, the investigators will measure participant sleep quality and fat metabolism overnight. In the morning, the investigators will perform a metabolic test to assess the responses of certain hormones. Findings from this study will identify how exercise influences novel contributors to metabolic syndrome (sleep quality and nocturnal metabolism) and shed light on some potential mechanisms to explain the variability in exercise responses.

Metabolic syndrome (MetS) is a major risk factor for many chronic diseases, including diabetes and cardiovascular disease. Sleep is recognized a risk factor for many of the conditions comprising MetS (e.g. high blood sugars, obesity). Interestingly, fat metabolism during your sleep is important for regulating several key components of health, like risk of obesity and glucose tolerance. While exercise is recognized as a health enhancing behavior to reduce the risk of many chronic diseases, the effect of exercise on sleep quality and nocturnal fat metabolism is largely unknown. This study plans to learn more about how the time of day that you perform exercise influences sleep quality and fat metabolism overnight in adults with metabolic syndrome. In this study, exercise will be performed in the early evening and the investigators will measure your sleep quality and fat metabolism overnight in our metabolic room. Findings from this study will identify how exercise influences novel contributors to metabolic syndrome (sleep quality and nocturnal metabolism) and shed light on some potential mechanisms to explain the variability in exercise responses.

Participants will arrive in the Clinical and Translation Research Center (CTRC) and enter the whole room calorimeter approximately 1 hour after arrival. During the evening exercise condition, participants will perform 45-minutes of moderate intensity continuous exercise on a treadmill 12 hours after habitual wake time in the evening. Participants will begin with a warm-up for 5 minutes at 2.0-2.5 mph. Heart rate will be monitored continuously with a heart rate monitor. Participants will maintain heart rate at 65% of age-predicted maximum heart rate. Throughout the day, participants will be required to eat the standardized meals provided at breakfast lunch and dinner. At the time of bed, participants will be instructed to turn off the lights, lay down in bed and to refrain from using electronic devices. In the morning, a metabolic test will be performed and melatonin levels will be measured in the saliva

Participants will arrive in the Clinical and Translation Research Center (CTRC) in the morning within 2 hours of their habitual wake time. Participants will enter the whole room calorimeter approximately 1 hour after arriving at the CTRC. Throughout the day, participants will be required to eat the standardized meals provided at breakfast lunch and dinner. At the time of bed, participants will be instructed to turn off the lights, lay down in bed and to refrain from using electronic devices. In the morning, a metabolic test will be performed and melatonin levels will be measured in the saliva

Participants will perform 4 study visits over 1-3 months. The 1st study visit is a screening visit, during which eligibility will be determined. During the 2nd visit, resting metabolic rate (RMR) and body composition will be measured. Participants will also perform a submaximal exercise test. Prior to each condition, habitual sleep/wake patterns will then be measured for 1 week. Participants will then perform each of the 2 study conditions (evening exercise and control) in randomized order with at least a 1-week washout period between conditions. Females will be studied during the luteal phase to control for potential confounding effects of hormonal variations across the menstrual cycle.

Inclusion Criteria: not currently meeting physical activity guidelines (<150 minutes moderate to vigorous physical activity per week); weight stable (<5% change in weight over the last 6 months); habitual sleep duration of 7-8 hours and consistent sleep/wake schedule (<1 hour variation night-to-night). Exclusion Criteria: body mass index >35.0 kg/m2; pregnancy; post-menopausal status in women, confirmed by absences of menses for >1 year and elevated follicular stimulating hormone concentrations (>50 mIU/mL); women on oral contraceptives; self-reported diabetes, cardiovascular disease, or sleep disorder; untreated hyper/hypothyroidism, cancer; inability to perform moderate to vigorous treadmill exercise; shiftwork