Healthy, Overweight and Obesity
Conditions
Brief summary
This study plans to learn more about metabolic responses to aerobic exercise at different times of the day (morning or evening) under fasting versus fed conditions.
Detailed description
This study plans to learn more about metabolic responses to aerobic exercise at different times of the day (morning or evening) under fasting versus fed conditions. Specifically, the investigators will explore the effect of fasted and fed AM and PM aerobic exercise on exercise energy expenditure and substrate oxidation, explore the effect of fasted and fed AM and PM aerobic exercise on plasma metabolites and lipids, and explore the effect of fasted-AM and Fasted-PM on 24h energy expenditure, 24h substrate metabolism, 24h glucose, and 24h profiles of hormonal regulators of energy metabolism
Interventions
BEHAVIORALFasted-AM
Participants will engage in aerobic exercise within 4 hours of waking up, following a \>10h overnight fast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at \ 08:00, \ 13:00, and \ 19:00. Plasma metabolite samples will be drawn immediately pre- and post- exercise.
BEHAVIORALFed-AM
Participants will engage in exercise within 4 hours of waking up, approximately 1h after consuming breakfast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at \ 07:00, \ 12:00, and \ 18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise.
BEHAVIORALFasted-PM
Participants will engage in exercise between 8-12 hours after waking up, following a \ 10h fast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at \ 07:00 and \ 18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise.
BEHAVIORALFed-PM
Participants will engage in exercise between 8-12 hours after waking up, approximately 1h after consuming dinner across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at \ 07:00, \ 12:00, and \ 18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise.
Sponsors
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
University of Colorado, Denver
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
* Age 18-40 years * Body Mass Index 18.5-\<40 kg/m2 * Recreationally active: defined as \>100 minutes per week of voluntary exercise at moderate intensity or greater and \>60 min per day of total habitual physical activity (i.e., work related, transportation related) at moderate intensity or greater, over the past 3 months. * No self-report of acute or chronic disease (cardiovascular disease (CVD), diabetes, pulmonary, gastrointestinal disorders, and orthopedic problems in particular). * No plans to relocate within the next 6 months. * No plans for extended travel (\>2 weeks) within the next 6 months. * Live or work within 30 minutes of the AHWC (exceptions may be made at the discretion of the Study PI on a case-by-case basis for highly motivated subjects). * Capable and willing to give informed consent, understand
Exclusion criteria
, and adhere to study conditions. * Have a primary care physician (or are willing to establish care with a primary care physician prior to study enrollment) to address medical issues which may arise during screening or study procedures. * No contraindications to exercise or limitations on ability to be physically active. * Ability to complete AM or PM exercise and complete 4 exercise sessions per week. * Ability to adhere to eating and exercise protocols (meal timing, exercising in fasted and fed states) * Willing and able to wear activity/sleep monitor for 7 consecutive days. * Willing not to enroll in any other formal weight loss or physical activity programs over the next 6 months. * For Females: * Not currently pregnant or lactating. * Not pregnant within the past 6 months. * Not planning to become pregnant in the next 6 months
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Exercise Energy Expenditure (kcals) | Fasted-AM Day 5, Fed-AM Day 5, Fasted-PM Day 5, Fed-PM Day 5 | On Day 5 of each condition, participants will complete a 45-minute exercise test on the treadmill to compare exercise energy expenditure and fat oxidation between. O2 and CO2 content of expired air will be measured continuously by open circuit spirometry and averaged every minute using an automated online system (TrueMax 2400; Parvo-Medics, Sandy, UT). Exercise energy expenditure will be determined from minute-by-minute values, measured in kcals. |
| Substrate Oxidation (Respiratory Quotient) | Fasted-AM Day 5, Fed-AM Day 5, Fasted-PM Day 5, Fed-PM Day 5 | On Day 5 of each condition, participants will complete a 45-minute exercise test on the treadmill to compare exercise energy expenditure and fat oxidation between. O2 and CO2 content of expired air will be measured continuously by open circuit spirometry and averaged every minute using an automated online system (TrueMax 2400; Parvo-Medics, Sandy, UT). Substrate Oxidation will be determined from minute-by-minute values, measured in respiratory quotient. |
Countries
United States
Outcome results
None listed