Clinical trial NCT03922685: Effects of Diet and Exercise on Circadian Glycemia
Official title: Control of Postprandial Glycemia: the Roles of Diet and Exercise
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Glucose Intolerance
Lead sponsor: University of Michigan
Sponsor class: OTHER
Collaborators: name: Northern Michigan University
First posted: 2019-04-22
Enrollment: 8
Sex: FEMALE
Minimum age (years): 50
Maximum age (years): 65
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: CROSSOVER
Intervention model description: The same eight subjects participated in counterbalanced order in:

(1) sedentary morning trial, (2) exercise morning trial, (3) sedentary evening trial, (4) exercise evening trial.
Primary purpose: BASIC_SCIENCE

Brief summary: Specific aims of the study are:

1. to evaluate whether a 24-h exposure to a 25%-carbohydrate diet will reduce postprandial glycemia to the same extent in the evening (19 h) as in the morning (7 h),. and
2. to determine whether one hour of post-meal moderate intensity exercise (at 50% of maximal effort) will further reduce postprandial glycemia.

The outcome measures are: plasma concentrations of glucose, insulin, glucose-dependent-insulinotropic peptide (GIP), leptin, and the ketone body beta-hydroxybutyrate.

Detailed description: The two hypotheses in this study are:

1. A 24-h exposure to a 25%-carbohydrate diet will reduce postprandial glycemia to the same extent in the evening (19 h) as in the morning (7 h), and
2. One hour of moderate-intensity exercise (at 50% of maximal effort) will further reduce postprandial glycemia to the same extent in the evening (19 h) as in the morning (7 h).

Eight postmenopausal subjects (age 58.5 years, BMI 25.6 kg/m2) participated in 4 24-h long crossover trials, two terminating at 7h and the other 2 at 19h. At each circadian time one trial required 60 minutes of moderate-intensity exercise (50% of maximal effort), and the other two involved no exercise.

Three 25%-carbohydrate meals prepared by the Michigan Clinical Research Unit (MCRU) kitchen, were eaten at subjects' home, and the fourth was eaten 20 minutes after subjects' arrival at MCRU at either 19 h or 7 h. Blood was collected from antecubital catheter at 10-minute intervals until 23:20 h or 11:20 h, respectively.Plasma was treated with protease inhibitor to preserve GIP, frozen at -80o C until glucose measurements by glucose oxidase, hormone measurements by chemiluminescence, and ketone measurements by Abbott meter strips.

Exercise intensity was determined before the exercise trials on a treadmill from oxygen consumption (VO2) and carbon dioxide production (VCO2) by subjects walking on a treadmill at 3 mph with the treadmill slope increased by 2% every 3 minutes. Maximal effort was established when respiratory exchange ratio (VCO2/VO2) reached or exceeded 1. The treadmill speed and slope at half maximal effort was used during the one-hour exercise bout which was initiated 40 minutes after the start of the meal.

Eligibility criteria: Inclusion Criteria:

* postmenopausal
* normal blood glucose
* no cholesterol medication
* age between 50 an 65 years
* overweight but not obese
* BMI between 25 and 30 kg/m2
* weight-stable during past 6 months
* exercise less than 20 minutes three times a week

Exclusion Criteria:

* metabolic disease other than hormonally-corrected hypothyroidism
* musculo-skeletal disability that would preclude exercise
* smoker
* do not meet inclusion criteria

Primary outcomes:
measure: Postprandial glucose concentration
timeFrame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials
measure: Postprandial insulin concentration
timeFrame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials
Secondary outcomes:
measure: Postprandial glucose-dependent insulinotropic peptide (GIP) concentration
timeFrame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials
measure: Postprandial beta-hydroxybutyrate concentration
timeFrame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials
measure: Postprandial leptin concentration
timeFrame: Four hours: 19:20 to 23:20 in the evening trials; 7:20 to 11:20 in the morning trials
Other outcomes:
Locations:
Study officials:
affiliation: Professor Emerita
name: Katarina T Borer, Ph.D.
role: PRINCIPAL_INVESTIGATOR
References: