Exercise and Time of Day in Type 2 Diabetes

Exercise Time of Day for Cardiometabolic Health in Type 2 Diabetes

The overall purpose of the study is to test the effect exercise time of day in adults with type 2 diabetes or prediabetes. The overarching hypothesis is that afternoon exercise in the afternoon may promote better changes in metabolic and vascular insulin sensitivity. We anticipate that these changes will correlate with glycemic control and blood pressure changes.

Study Overview

• Status: Completed
• Conditions: Diabetes Mellitus, Type 2; PreDiabetes
• Intervention / Treatment: Behavioral: Morning Exercise; Behavioral: Afternoon Exercise

Detailed Description

Type 2 diabetes (T2D) is associated with a 3-fold cardiovascular disease (CVD) mortality risk compared with healthy controls, and it is estimated that 30 million adults in the United States have the disease. In recent years the American Diabetes Association (ADA) and American College of Sports Medicine (ACSM) recommend moderate intensity (40-60% heart rate max, HRmax) aerobic exercise 3-5d/wk for the management of T2D. The statement also recognized that higher exercise intensity (>60% HRmax) predicts better blood glucose control than exercise volume. Cardiovascular health (e.g. fitness, blood pressure, etc.) also appears to respond in an exercise dose dependent manner. Despite these suggestions, many people exercising compensate by eating calories back from exercise, thereby negating weight loss. Moreover, compliance and adherence to exercise and diet medical counsel is disappointingly low.

Recent work has begun to target the best time of day to exercise in effort to improve weight loss and related health. This has evolved in part since circadian biology reveals people tend to become glucose intolerant, and develop insulin resistance and endothelial dysfunction in the evening compared with morning. As a result, it would be reasonable to hypothesize that exercise in the afternoon may be best at combating natural declines in health as well as optimizing training adaptations. However, not all studies agree that afternoon is the best time to exercise. In fact, some have demonstrated that 12 wks of aerobic plus resistance exercise improved glycemic control whether performed in the morning or afternoon in adults with T2D. Moreover, consistent morning exercise has been suggested to improve exercise adherence through possible enjoyment as well as lead to greater weight loss. Taken together, additional work is warranted to understand time of day in which exercise is performed given circadian influence may contribute to variations in favorable metabolic as well as vascular adaptation for CVD prevention/treatment. Excitingly, we have preliminary data showing that afternoon exercise induces greater weight loss, reductions in food intake as well as perceptions of appetite and increased insulin sensitivity when compared to morning exercisers. Thus, the overall purpose of this proposal is to determine whether exercise time of day differentially enhances likelihood of weight loss via appetite regulation as well as glycemic control. Our overarching hypothesis is that afternoon exercise will enhance the effectiveness of exercise to induce weight loss, improve appetite and improve glycemic regulation compared to exercise in the morning. Taken together, findings from this study will inform public health recommendations to contemporary behavioral strategies to treat T2D. The study will also provide much needed experimental evidence to time of day in which exercise is performed influences public health risk.

• Study Type: Interventional
• Enrollment (Actual): 36
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • New Jersey
    • New Brunswick, New Jersey, United States, 08901
      • Robert Wood Johnson University Hospital Clinical Research Center
    • New Brunswick, New Jersey, United States, 08901
      • Rutgers University Loree Gymnasium
    • New Brunswick, New Jersey, United States, 08901
      • New Jersey Institute for Food, Nutrition, and Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Male or female >30 and <80 years old.
• Has a body mass index >25 and <45 kg/m2.
• Previously diagnosed with prediabetes and/or T2D.
• If not previously diagnosed, has a fasting blood glucose ≥ 100 mg/dL and/or HbA1c ≥ 5.7%

Exclusion Criteria:

• Morbidly obese patients (BMI >45 kg/m2) and lean patients (BMI <25 kg/m2)
• Evidence of type 1 diabetes and diabetics requiring insulin therapy.
• Subjects who have not been weight stable (>2 kg weight change in past 3 months)
• Subjects who have been recently active (>30 min of moderate/high intensity exercise, 3 times/week).
• Subjects who are smokers or who have quit smoking <1 years ago
• Subjects with abnormal estimated glomerular filtration rate (eGFR).
• Hypertriglyceridemic (>400 mg/dl) and hypercholesterolemic (>260 mg/dl) subjects
• Hypertensive (>160/100 mmHg)
• Subjects with a history of significant metabolic, cardiac, congestive heart failure, cerebrovascular, hematological, pulmonary, gastrointestinal, liver, renal, or endocrine disease or cancer that in the investigator's opinion would interfere with, alter the outcome measures, or impact subject safety.
• Pregnant (as evidenced by positive urine pregnancy test) or nursing women.
• Subjects with contraindications to participation in an exercise training program
• Currently taking active weight suppression medication (e.g. phentermine,orlistat, lorcaserin, naltrexone-bupropion in combination, liraglutide, benzphetamine, diethylpropion, phendimetrazine)
• Known hypersensitivity to perflutren (contained in Definity)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Morning Exercise; If participants are randomly assigned to this group, they will participate in exercise training in the morning (between 7:00am - 11:00am) at an exercise intensity ~85% VO2max. Participants will be asked to regularly engage in morning exercise while supervised for about 2 weeks.	Behavioral: Morning Exercise; Sixty minutes of supervised exercise at an intensity ~85% VO2max will be performed in the morning (between 7:00am - 11:00am) for up to 10 sessions.
Active Comparator: Afternoon Exercise; If participants are randomly assigned to this group, they will participate in exercise training in the afternoon (between 4:00pm - 8:00pm) at an exercise intensity ~85% VO2max. Participants will be asked to regularly engage in afternoon exercise while supervised for about 2 weeks.	Behavioral: Afternoon Exercise; Sixty minutes of supervised exercise at an intensity ~85% VO2max will be performed in the afternoon (between 4:00pm - 8:00pm) for up to 10 sessions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body Weight	The primary outcome is changes in body weight pre- and post-intervention	Over the course of 2 weeks.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Glucose Tolerance	We will examine the influence of Noom on the glucose area under the curve during the oral glucose tolerance test.	Over the course of 2 weeks.
Flow-mediated dilation	We will assess blood flow to better understand nutrient/glucose delivery.	Over the course of 2 weeks.

Collaborators and Investigators

• Sponsor: Rutgers, The State University of New Jersey
• Collaborators: Noom Inc.
• Investigators: Principal Investigator: Steven K Malin, PhD, Rutgers University - New Brunswick

Study record dates

Study Major Dates

• Study Start (Actual): September 25, 2021
• Primary Completion (Actual): December 17, 2025
• Study Completion (Actual): December 18, 2025

Study Registration Dates

• First Submitted: October 26, 2021
• First Submitted That Met QC Criteria: October 26, 2021
• First Posted (Actual): November 5, 2021

Study Record Updates

• Last Update Posted (Actual): May 18, 2026
• Last Update Submitted That Met QC Criteria: May 14, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: exercise; type 2 diabetes; continuous glucose monitoring; blood flow; cardiometabolic; behavioral; metabolic health; vascular health
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 2; Prediabetic State; Motor Activity; Behavior
• Other Study ID Numbers: Pro2021001183

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Data will be made available upon reasonable request to the PI after publication.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes