Does When You Exercise Matter? A Randomized Trial Comparing the Effect of Morning versus Evening Aerobic Exercise on Weight Loss and Compensatory Behaviors

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Description

If you join the study, you will undergo screening evaluations to see if you are eligible to be in the study. If you are eligible to be in the study, you will be randomized to one of two study groups. Which group you are assigned to will be chosen by chance by a procedure similar to the toss of a coin. Both study groups will receive an identical aerobic exercise training program which lasts 13 months. One group will be asked to complete all exercise sessions in the morning (6-10 AM) and the other group will be asked to complete all exercise sessions in the late afternoon/evening (3-7 PM). The exercise training will progress to burning 2000 calories per week with moderate to vigorous intensity aerobic exercise. Both AM and PM exercise groups will perform 4 sessions of exercise per week during their randomized exercise time. You will wear a heart rate monitor for all exercise sessions and your exercise data will be viewed by study staff. During the first 7 months of the exercise program, three exercise sessions per week will be “supervised”, which means they will be monitored by study staff and completed at the Anschutz Health and Wellness Center (AHWC) exercise facility. During the first 7 months of the exercise program, one additional exercise session per week will be completed “on-own”, which means that you will be able to exercise at another location if you want. After you complete the first 7 months of the exercise program, you will be asked to perform 4 exercise sessions per week on your own for another 6 months. You will be asked to continue exercising during your randomized group time (AM or PM) and continue to wear the heart rate monitor during exercise. We will provide you with a membership to the AHWC exercise facility during this entire 13 month exercise program. Your participation in the study will last approximately 16 months to complete all study measures including study screening and baseline testing. During the study, you will be asked not to participate in any other weight loss, exercise, or diet programs and not to participate in any other research studies that might change your weight. During the study, you will be asked not to take any weight loss medications or weight loss supplements. If you are a female and you can become pregnant, you will be asked not to become pregnant and to use a reliable method of birth control during the study.

Details
Age

Adult

Eligibility

&#8226; Age 18-55 years &#8226; Body Mass Index 25-40 kg/m2 &#8226; Physically inactive: defined as self-reporting <150 minutes per week of physical activity at moderate intensity or greater on a regular basis over the past 3 months. &#8226; No self-report of acute or chronic disease (cardiovascular disease (CVD), diabetes, gastrointestinal disorders and orthopedic problems in particular) &#8226; No plans to relocate within the next 15 months. &#8226; No plans for extended travel (> 2 weeks) within the next 13 months &#8226; Live or work within 30 minutes of the AHWC &#8226; No contraindications to exercise or limitations on ability to be physically active. &#8226; Willing to be randomized to either AM or PM exercise and complete 4 exercise sessions per week. &#8226; Fully vaccinated, or willing to be fully vaccinated, against COVID-19 prior to study enrollment (fully vaccinated is defined as at least 2 weeks post final vaccine dose). &#8226; For Females -Not currently pregnant or lactating -Not pregnant within the past 6 months -Not planning to become pregnant in the next 15 months; sexually active women of childbearing potential may be enrolled if they have had a tubal ligation or use a reliable means of contraception

Exclusion Criteria: • Diastolic blood pressure > 100 mm HG or systolic blood pressure > 160 mm HG. • Resting heart rate >100 • Diabetes (fasting glucose ≥126 mg/dL or Hemoglobin A1C ≥6.5%) • Undiagnosed hypo- or hyper-thyroidism (TSH outside of the normal range) or history of uncontrolled thyroid disorder. History of thyroid disease or current thyroid disease treated with a stable medication regimen for at least 6 months is acceptable. • Hematocrit, white blood cell count or platelets significantly outside the normal reference range. • Clinically significant abnormalities in hematocrit, white blood cell count or platelets. • Triglycerides > 400 mg/dL • LDL cholesterol >200 mg/dL • Abnormal resting electrocardiogram (ECG) • Presence or history of any metabolic or chronic health problems which would affect appetite, food intake, energy metabolism, or ability to optimally participate in the exercise component including: CVD, peripheral vascular disease, cerebrovascular disease, significant cardiac arrhythmias or cardiac valve disease, diabetes, uncontrolled hyper- or hypothyroidism, uncontrolled hypertension, cancer (within the last 5 years, except skin cancer or other cancers considered cured with excellent prognosis), HIV infection, significant gastrointestinal disorders (described below), significant pulmonary disorders (described below), significant renal, musculoskeletal, neurologic, hematologic, or psychiatric disease. • Significant gastrointestinal disorders • Significant pulmonary disorders including • Symptoms suggestive of CVD • Regular use of prescription or over-the-counter medications known to significantly impact appetite, weight, sleep, or energy metabolism • Use of medications that would impact ability to achieve age-predicted maximum heart rate • Regular use of systemic steroids (other than Oral Contraceptive Pills) • Regular use of obesity pharmacotherapeutic agents within the last 6 months. • Previous obesity treatment with surgery or weight loss device, except: (1) liposuction and/or abdominoplasty if performed > 1 year before screening, (2) lap banding if the band has been removed > 1 year before screening, (3) intragastric balloon if the balloon has been removed > 1 year before screening (4) duodenal-jejunal bypass sleeve, if the sleeve has been removed > 1 year before screening or 5) AspireAssist or other endoscopically placed weight loss device if the device has been removed > 1 year before screening. • Current alcohol or substance abuse • Nicotine use (past 6 months) • History of clinically diagnosed eating disorders including anorexia nervosa, bulimia, binge eating disorder. • Current severe depression or history of severe depression within the previous year, based on DSM-IV-TR criteria for Major Depressive Episode. • History of other significant psychiatric illness (e.g. psychosis, schizophrenia, mania, bipolar disorder) • Night-time shiftwork, rotating work, irregular sleep/wake patterns or other scheduling constraints which may hinder ability to consistently exercise at specific times of the day. • Urinary incontinence or retention • Weight loss >5% in past 3 months. • Weight gain >10% in past 3 months • Weight loss of >50 lbs in past 3 years for any reason except post-partum weight loss • Currently participating in or planning to participate in any formal weight loss, dietary modification, or physical activity/exercise programs or clinical trials.

Type of Study

Outcomes Research

Principal Investigator
Photograph of Victoria Catenacci,  MD

Victoria Catenacci, MD

Study ID

Protocol Number: 21-3094

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