An interventional study of Hourly 3-Minute Light Walking Breaks and Hourly Stair-Climbing Exercise Snacks in Prediabetes, sponsored by St. Louis University. Recruiting at 1 site in United States. Open to participants aged 18 Years to 69 Years. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by St. Louis University · Not applicable, Interventional, and Treatment
This study will examine whether very short bouts of stair climbing performed throughout the day can improve blood sugar control and cardiovascular health in adults with prediabetes. Participants will complete three separate study visits in random order: uninterrupted sitting, sitting interrupted by 3-minute light walking breaks each hour, and sitting interrupted by brief stair-climbing exercise "snacks" each hour.
During each visit, the research team will measure glucose, insulin, blood lipids, markers of inflammation and oxidative stress, and blood-vessel function. Continuous glucose monitors, blood samples, heart-rate and blood-pressure measurements, vascular ultrasound, and questionnaires will be used to assess the participants' responses.
The goal of the study is to determine whether brief stair-climbing breaks may be a practical way to reduce the negative effects of prolonged sitting and improve metabolic health in adults with prediabetes.
This is a single-site, randomized, counterbalanced crossover pilot study evaluating the acute metabolic, vascular, and behavioral effects of interrupting prolonged sitting with brief stair-climbing exercise snacks in adults with prediabetes. A total of 20 participants will complete all three experimental conditions in randomized order, with a washout period of at least 7 days between visits.
The three experimental conditions are: (1) uninterrupted sitting, (2) sitting interrupted each hour by a 3-minute light walking break, and (3) sitting interrupted each hour by a brief stair-climbing exercise snack consisting of approximately 20 seconds of stair ascent at a fast but safe self-selected pace.
Participants will attend each experimental visit after an overnight fast. Two standardized meals will be provided during each approximately 6-hour experimental visit: Meal 1 at the beginning of the postprandial testing period and Meal 2 approximately 180 minutes later. Metabolic responses will be assessed using continuous glucose monitoring and serial blood sampling for glucose, insulin, lipids, inflammatory markers, and oxidative stress markers. Vascular responses will be assessed using noninvasive ultrasound. Heart rate, blood pressure, ratings of perceived exertion, symptoms, and participant-reported feasibility and acceptability will also be assessed.
The study is designed to determine whether brief hourly stair-climbing exercise snacks improve postprandial glucose and insulin responses and other cardiometabolic outcomes compared with uninterrupted sitting and light walking breaks, and to explore the feasibility and acceptability of this approach in adults with prediabetes.
Age 18 to 69 years, inclusive. Body mass index (BMI) 25.0 to 40.0 kg/m², inclusive.
Objectively confirmed prediabetes based on at least one of the following:
Able to understand study procedures and provide written informed consent in English.
Able to safely perform repeated walking and vigorous stair-climbing activity based on medical history, resting vital signs, PAR-Q+ responses, investigator assessment, and medical clearance when required.
Able to safely undergo repeated venous blood collection and IV-catheter placement.
Able to safely consume the standardized study meals. Willing and able to complete all three experimental conditions and comply with fasting, dietary, physical-activity, medication, and pre-visit standardization instructions.
Exclusion Criteria:
BMI below 25.0 kg/m² or above 40.0 kg/m². Diagnosed type 1 or type 2 diabetes mellitus. Laboratory findings that do not confirm prediabetes or that suggest diabetes, including HbA1c ≥6.5%, fasting plasma glucose ≥126 mg/dL, or 2-hour plasma glucose ≥200 mg/dL during a 75-g oral glucose tolerance test.
Cardiovascular, pulmonary, musculoskeletal, neurological, or other medical conditions that would preclude safe participation in the walking or stair-climbing interventions.
Resting vital signs, current symptoms, or other screening findings indicating that exercise participation would be unsafe.
Pregnancy, plans to become pregnant during the study period, or breastfeeding. Current use of medications that may substantially affect glucose metabolism, lipid metabolism, body weight, study outcomes, or safe participation, including insulin, glucose-lowering medications, GLP-1 receptor agonists, pharmacologic weight-loss medications, systemic corticosteroids, or other medications judged by the investigator to interfere with study outcomes or safety.
Contraindications to vascular ultrasound, repeated blood collection, IV-catheter placement, or exercise participation.
Food allergies, intolerances, or dietary restrictions that prevent safe consumption of the standardized study meals.
Known allergy or severe skin sensitivity to adhesives used with continuous glucose monitors.
Bleeding disorder, current anticoagulant use, history of anemia, recent blood donation, recurrent fainting during blood collection, difficult venous access, or another condition judged to create unacceptable risk from repeated blood sampling or IV-catheter placement.
Inability to safely perform repeated walking or stair climbing. PAR-Q+ result requiring further medical evaluation when the participant does not obtain required written medical clearance.
Any other condition or finding that, in the judgment of the Principal Investigator or qualified study investigator, would make participation unsafe or substantially interfere with completion of study procedures.
Participants will remain seated throughout the approximately 6-hour experimental visit, except as needed for study procedures. At the time points corresponding to activity bouts in the walking and stair-climbing conditions, participants will remain seated. This condition serves as the sedentary control condition.
Participants will interrupt prolonged sitting with a 3-minute light walking break at approximately 30, 90, 150, 210, 270, and 330 minutes during the approximately 6-hour experimental visit. Walking breaks will therefore occur at 60-minute intervals.
Behavioral: Hourly 3-Minute Light Walking Breaks
Participants will interrupt prolonged sitting with brief stair-climbing exercise snacks at approximately 30, 90, 150, 210, 270, and 330 minutes during the approximately 6-hour experimental visit. During each bout, participants will ascend approximately three flights of stairs at a fast but safe self-selected pace for about 20 seconds.
Behavioral: Hourly Stair-Climbing Exercise Snacks
Participants will interrupt prolonged sitting with a 3-minute light walking break at approximately 30, 90, 150, 210, 270, and 330 minutes during the approximately 6-hour experimental visit. Activity breaks are therefore separated by approximately 60 minutes. Participants will otherwise remain seated except as required for study procedures.
Participants will interrupt prolonged sitting with brief stair-climbing exercise snacks at approximately 30, 90, 150, 210, 270, and 330 minutes during the approximately 6-hour experimental visit. During each bout, participants will ascend approximately three flights of stairs at a fast but safe self-selected pace for about 20 seconds. Participants will not run or skip steps, and use of the handrail will be permitted as needed.
6-Hour Postprandial Glucose Area Under the Curve (AUC)
Plasma glucose will be measured from a fasting venous blood sample obtained before Meal 1 and from serial venous blood samples collected every 30 minutes through 360 minutes after Meal 1 completion. Meal 1 completion will define the start of the postprandial period, and a second standardized meal will be provided at approximately 180 minutes. Plasma glucose AUC will be calculated across the 6-hour experimental period and compared among uninterrupted sitting, hourly 3-minute light walking breaks, and hourly stair-climbing exercise snacks.
Time frame: From fasting baseline before Meal 1 through 360 minutes after Meal 1 completion
6-Hour Postprandial Plasma Insulin Area Under the Curve (AUC)
Plasma insulin will be measured from a fasting venous blood sample obtained before Meal 1 and from prespecified serial venous blood samples collected through 360 minutes after Meal 1 completion. Meal 1 completion will define time 0, and a second standardized meal will be provided at approximately 180 minutes. Insulin AUC will be calculated across the 0- to 360-minute experimental period and compared among uninterrupted sitting, hourly 3-minute light walking breaks, and hourly stair-climbing exercise snacks.
Time frame: From fasting baseline before Meal 1 through 360 minutes after Meal 1 completion
6-Hour Postprandial Plasma Free Fatty Acid Response
Plasma free fatty acids will be measured from prespecified serial venous blood samples collected during each experimental visit. A fasting baseline sample will be obtained before Meal 1, followed by postprandial sampling through 360 minutes after Meal 1. Free fatty acid responses across the postprandial period will be compared among uninterrupted sitting, hourly 3-minute light walking breaks, and hourly stair-climbing exercise snacks.
Time frame: From fasting baseline before Meal 1 through 360 minutes after Meal 1 completion
6-Hour Postprandial Plasma Triglyceride Response
Plasma triglycerides will be measured from prespecified serial venous blood samples collected during each experimental visit. A fasting baseline sample will be obtained before Meal 1, followed by postprandial sampling through 360 minutes after Meal 1. Triglyceride responses across the postprandial period will be compared among the three experimental conditions.
Time frame: From fasting baseline before Meal 1 through 360 minutes after Meal 1 completion
Postprandial Plasma Malondialdehyde (MDA)
Plasma malondialdehyde (MDA), a marker of oxidative stress, will be measured from prespecified venous blood samples collected during each experimental visit. A fasting baseline sample will be obtained before Meal 1, with postprandial assessment through 360 minutes after Meal 1. MDA responses will be compared among uninterrupted sitting, hourly 3-minute light walking breaks, and hourly stair-climbing exercise snacks.
Time frame: From fasting baseline before Meal 1 through 360 minutes after Meal 1 completion
Postprandial Plasma Inflammatory Cytokines (TNF-α and IL-6)
Plasma tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) will be measured from prespecified venous blood samples collected during each experimental visit. A fasting baseline sample will be obtained before Meal 1, with postprandial assessment through 360 minutes after Meal 1. TNF-α and IL-6 responses will be compared among uninterrupted sitting, hourly 3-minute light walking breaks, and hourly stair-climbing exercise snacks.
Time frame: From fasting baseline before Meal 1 through 360 minutes after Meal 1 completion
Change in Superficial Femoral Artery Diameter
Superficial femoral artery diameter will be assessed using noninvasive Duplex ultrasound before and after each experimental condition. B-mode ultrasound images will be used to quantify arterial diameter, and changes will be compared among uninterrupted sitting, hourly light walking breaks, and hourly stair-climbing exercise snacks.
Time frame: Baseline before Meal 1 and at the end of the 6-hour experimental period, approximately 360 minutes after Meal 1 completion
Change in Superficial Femoral Artery Blood-Flow Velocity
Superficial femoral artery blood-flow velocity will be assessed using Doppler ultrasound before and after each experimental condition. Changes in blood-flow velocity will be compared among uninterrupted sitting, hourly light walking breaks, and hourly stair-climbing exercise snacks.
Time frame: Baseline before Meal 1 and at the end of the 6-hour experimental period, approximately 360 minutes after Meal 1 completion
Change in Superficial Femoral Artery Shear Pattern
Superficial femoral artery shear patterns will be derived from vascular ultrasound measurements obtained before and after each experimental condition. Changes in shear patterns will be compared among uninterrupted sitting, hourly light walking breaks, and hourly stair-climbing exercise snacks.
Time frame: Baseline before Meal 1 and at the end of the 6-hour experimental period, approximately 360 minutes after Meal 1 completion
Heart Rate Response to Activity Bouts
Heart rate will be recorded immediately before and immediately after each walking or stair-climbing bout, with measurements obtained at corresponding matched time points during the uninterrupted-sitting condition. Heart rate responses will be compared among the three experimental conditions.
Time frame: Immediately before and immediately after activity bouts at approximately 30, 90, 150, 210, 270, and 330 minutes after Meal 1 completion
Rating of Perceived Exertion During Activity Bouts
Rating of perceived exertion will be assessed using the Borg Rating of Perceived Exertion Scale (6-20) immediately after each walking and stair-climbing bout. Higher scores indicate greater perceived exertion. Ratings will be used to characterize perceived exercise intensity across the active conditions.
Time frame: Immediately after activity bouts at approximately 30, 90, 150, 210, 270, and 330 minutes after Meal 1 completion
End-of-Study Acceptability and Practicality Questionnaire Responses
Participants will complete the RISE UP End-of-Study Acceptability, Practicality, and Potential Adoption Questionnaire after the final experimental visit. Items assess acceptability, enjoyment, practicality, confidence, perceived usefulness, and willingness for future adoption. Agreement items use a 5-point response scale ranging from 1 (Strongly disagree) to 5 (Strongly agree). Higher scores indicate greater agreement with the individual statement. Because the questionnaire includes both positively and negatively worded items and no overall score will be calculated, higher scores do not uniformly indicate a better or worse outcome. Individual questionnaire items will be summarized separately.
Time frame: After completion of the final experimental visit, approximately 3 to 6 weeks after enrollment
Participant-Reported Barriers and Facilitators to Implementation
Participants will report perceived barriers and facilitators to implementing brief stair-climbing exercise snacks in daily life using questionnaire items and open-ended responses. Closed-ended barrier items use a 5-point response scale ranging from 1 (Strongly disagree) to 5 (Strongly agree), with higher scores indicating greater agreement that the specified factor represents a barrier. Open-ended responses will be summarized qualitatively. No overall barriers or facilitators score will be calculated.
Time frame: After completion of the final experimental visit, approximately 3 to 6 weeks after enrollment
Plan to share: Yes — De-identified individual participant data underlying the results reported in the primary publication may be shared upon reasonable request to the Principal Investigator, subject to institutional policies, applicable ethical and privacy requirements, and execution of an appropriate data-use agreement when required.
Supporting information: Study protocol, Sap
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