This randomized controlled crossover trial of 36 pregnant individuals with gestational diabetes (GDM) or gestational glucose intolerance (GGI) will: 1. Determine the effects of physical activity (PA) timing, specifically 30 minutes of moderate intensity walking or stepping in the morning (between 5am-9am, within 30-40 minutes of starting breakfast), versus late afternoon/evening (between 4pm-8pm, within 30-40 minutes of dinner) on glucose across the 24-hour cycle. 2. Explore the potential effects of the timing of PA on sleep and mood state.
Research participants will: 1. Exercise according to a schedule provided by the study for an 11-day period. They will complete either no exercise or 30 minutes of walking/stepping (e.g., stepping in place or around the house when walking outside is not an option or not an attractive option) on specifically assigned days, at specifically assigned times of day. 2. Wear a masked Dexcom G6 continuous glucose monitor (CGM) or unmasked Dexcom G7 CGM for the 11-day study period. 3. Wear a masked physical activity (PA) monitor watch (ActiGraph CentrePoint Insight Watch) on the non-dominant wrist for the 11-day study period (all day and all night). 4. Take pictures of all of food and drinks consumed, at the start and end (showing food and drink not eaten) of all eating occasions. Participants will use their phones to upload photos to a study website for the entire 11-day study period. Participants will also complete 24-hour dietary recall phone calls for 3 of the 11 study days (i.e., for 1 morning PA day, 1 late afternoon/evening PA day, and 1 no PA day, with the days randomly selected). 5. Complete electronic REDCap surveys, including daily surveys that assess: when (i.e., the exact times) they started eating breakfast, lunch, and dinner that day; when (e.g., the exact times) they went to bed and fell asleep for the night and woke up and got out of bed the next morning, and questions on the quality of their sleep; adverse events and issues with the study equipment (e.g., CGM); and mood state following PA (on days assigned 30 minutes of walking/stepping).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
HEALTH_SERVICES_RESEARCH
Masking
NONE
Enrollment
39
30 minutes of moderate intensity walking or stepping (i.e., at a pace of approximately 100 steps per minute), varied by time of day it is performed: morning (i.e., between 5am-9am, within 30-40 minutes of starting breakfast) versus late afternoon/evening (i.e., between 4pm-8pm, within 30-40 minutes of dinner).
The University of Tennessee Medical Center
Knoxville, Tennessee, United States
CGM glucose outcomes
Glucose outcome measures include: 24-hour glucose and coefficient of variation, daytime glucose, nighttime glucose, pre-breakfast area under the glucose curve (AUC; calculated for the 120 minutes prior to the start of breakfast), and all post-meal AUCs (calculated for the 120 minutes after the start of the breakfast, lunch and dinner).
Time frame: Throughout the 11-day study period
Duration of sleep
Self-reported length of each sleep period (in hours: minutes)
Time frame: Throughout the 11-day study period
Sleep efficiency
Self-reported percentage of time spent asleep while in bed (0-100%), for each sleep period
Time frame: Throughout the 11-day study period
Sleep quality
Self-reported quality of sleep (i.e., very poor, poor, fair, good, or very good), for each sleep period
Time frame: Throughout the 11-day study period
Mood
Mood following physical activity, using the short version of the Multi-Dimensional Mood Questionnaire (MDMQ, with 15 items) which measures self-reported mood states (i.e., scores range from 15-90, with higher scores indicating better mood state).
Time frame: Throughout the 11-day study period (i.e., on days assigned to physical activity)
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