Effectiveness of Aerobic Exercise to Mitigate Hyperglycemia After Fasted Resistance Exercise

Certain types and timings of exercise are known to cause hyperglycemia (high blood glucose) in people with type 1 diabetes. Hyperglycemia increases the risk of most long-term complications for individuals with this complication. However, using insulin corrections to treat post-exercise hyperglycemia can increase the risk of late-onset hypoglycemia (low-blood glucose).

Anaerobic activities performed in a fasted state are known to cause increases in blood glucose and post-exercise hyperglycemia in most individuals with type 1 diabetes. This study proposes to examine the effect of a ten-minute aerobic cool down after resistance exercise on the blood glucose response to fasted exercise of individuals with type 1 diabetes. It is hypothesized that adding a short aerobic cool down at the end of a fasted resistance exercise session will attenuate post-exercise increases in blood glucose observed in previous studies, leading to less post-exercise hyperglycemia.

Study Overview

• Status: Completed
• Conditions: Type 1 Diabetes
• Intervention / Treatment: Behavioral: Resistance exercise only; Behavioral: Resistance exercise plus cool down

Detailed Description

Individuals with type 1 diabetes (T1D), are at elevated risk of low muscular strength, as well as accelerated decline in muscle strength and functional status with aging. Resistance exercise (RE) is a proven intervention that has been demonstrated to improve physical function, muscle mass, body composition, mental health, bone mineral density, insulin sensitivity, blood pressure, lipid profiles, and cardiovascular health for all adults. Clinical guidelines recommend that individuals with T1D perform RE twice weekly to optimally benefit from RE yet most individuals with T1D are unable to meet these recommendations. Two barriers to exercise responsible for this discrepancy are a fear of hypoglycemia from exercise, and a loss of control over diabetes. To limit barriers to exercise, much research has been done to identify exercise modalities that have minimal risk for hypoglycemia, including recent investigations demonstrating a blood glucose increase leading to hyperglycemia in response to RE while participants are fasted. Hyperglycemia frequency is directly related to the incidence of diabetes-related complications, so exercise recommendations should minimize risk of hyperglycemic and hypoglycemic responses. Clinical guidelines for post-exercise hyperglycemia recommend a corrective insulin dose or a brief aerobic cool down, however the efficacy of an aerobic cool down has yet to be empirically tested. Additionally, overcorrection of hyperglycaemia with insulin after exercise can result in an increased risk of severe late onset hypoglycaemia, which could even be fatal.

The study will have a randomized, repeated measures design with two testing sessions (one with a cool down and one without a cool down) in addition to a baseline fitness assessment. Interested participants will be invited to the Physical Activity and Diabetes Laboratory on the main campus of the University of Alberta. Participants will be asked questions related to diabetes care, physical activity levels, and medication. Blood pressure and heart rate will also be measured. Where participants are eligible, anthropometric characteristics will be measured using standard protocols. Those who meet all eligibility criteria and complete informed consent forms will be asked to complete the initial exercise tests. Participants will perform a submaximal aerobic capacity test to extrapolate the participant's aerobic capacity. Participants will also undergo a strength test for each of the seven exercises involved in the study, in order to estimate the maximum weight they can move for 3 sets of 8 repetitions (8RM). During this session the investigators will introduce participants to the activity monitor (accelerometer) that will be worn on the day before, the day of, and the day after each testing session. The accelerometer will provide information on background physical activity and sleep patterns that might act as confounders where the blood glucose responses to exercise are concerned.

Testing sessions: Participants will be asked to arrive at the lab between 7:00 and 8:00 am for both sessions, which will be randomly assigned by tossing a fair coin. During the sessions, participants will be asked to perform a total of seven resistance exercises (leg press, chest press, leg curls, lat pulldowns, seated row, shoulder press, and abdominal crunches). The protocol will be 3 sets of 8 repetitions at the participant's 8 RM. Participants will be asked to match their daily food and insulin intake as closely as possible from one testing session to the next for the day before, day of and day after the testing session. During this time participants will also wear an accelerometer on their waist during the day, and on their non-dominant wrist at night. Participants will be provided with log sheets to assist in both of these tasks and will also be asked to avoid strenuous exercise and alcohol intake.

A CGM sensor will be subcutaneously inserted by one of the investigators (trained by a group from the CGM manufacturer) into the anterior abdominal area of the participant approximately 2 days prior to the first testing session. The Dexcom G6 CGM will store glucose data every 5 minutes for up to 10 days. The participant will be instructed on how to remove their sensor at least 24 hours after the exercise session, and will be asked to upload their data to Dexcom Clarity to share with the study team. If the participant habitually uses their Dexcom G6 in their diabetes care, they will be provided with the option to start their own CGM for the study.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Alberta
    • Edmonton, Alberta, Canada, T6G 2E1
      • University of Alberta

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 55 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• diagnosed with type 1 diabetes for more than 12 months
• using either multiple daily insulin injections or continuous subcutaneous insulin infusion
• willing and able to perform resistance exercise
• HbA1c < 10.0%
• ability to attend laboratory-based sessions at the University of Alberta in Edmonton

Exclusion Criteria:

• HbA1c >9.9%
• Frequent and unpredictable hypoglycaemia
• A change in insulin management strategy within two months of the study
• blood pressure > 144/95
• severe peripheral neuropathy
• a history of cardiovascular disease
• musculoskeletal injuries affecting the ability to perform resistance exercise.
• treatment with medications (other than insulin) that affect glucose metabolism (e.g. atypical antipsychotics, corticosteroids)
• body mass index >30kg/m2
• smoking
• moderate to high alcohol intake (>2 drinks per day)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: All participants; All participants will undergo two separate testing sessions	Behavioral: Resistance exercise only; Participants will perform 3 sets of 8 repetitions of 7 different exercises while in a fasted state.; Behavioral: Resistance exercise plus cool down; Participants will perform 3 sets of 8 repetitions of 7 different exercises while in a fasted state followed by a 10-minute light aerobic cool down

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
percent time spent in hyperglycemia	amount of time spent with interstitial glucose (measured by continuous glucose monitoring) greater than 9.9 mmol/L	6 hours post exercise, overnight post exercise (midnight to 6 am) and 24 hours post exercise

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
mean continuous glucose monitoring (CGM) glucose	mean values of interstitial glucose levels measured by CGM	6 hours post exercise, overnight post exercise (midnight to 6 am) and 24 hours post exercise
frequency of hyperglycemia	number of times that CGM glucose is equal to or greater than 10.0 mmol/L	6 hours post exercise, overnight post exercise (midnight to 6 am) and 24 hours post exercise
frequency of hypoglycemia	number of times that CGM glucose is equal to or lower than 3.9 mmol/L	6 hours post exercise, overnight post exercise (midnight to 6 am) and 24 hours post exercise
percent time spent in hypoglycemia	percentage of time that CGM glucose is equal to or less than 3.9 mmol/L	6 hours post exercise, overnight post exercise (midnight to 6 am) and 24 hours post exercise
percent time in range	percentage of time that CGM glucose is between 4.0 and 9.9 mmol/L	6 hours post exercise, overnight post exercise (midnight to 6 am) and 24 hours post exercise
capillary glucose	change in capillary glucose during exercise	from 0 minutes to 45 minutes (during exercise)

Collaborators and Investigators

• Sponsor: University of Alberta

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2022
• Primary Completion (Actual): March 19, 2023
• Study Completion (Actual): March 19, 2023

Study Registration Dates

• First Submitted: January 10, 2022
• First Submitted That Met QC Criteria: January 10, 2022
• First Posted (Actual): January 24, 2022

Study Record Updates

• Last Update Posted (Actual): March 29, 2023
• Last Update Submitted That Met QC Criteria: March 27, 2023
• Last Verified: March 1, 2023

More Information

Terms related to this study

• Keywords: resistance exercise, aerobic exercise
• Additional Relevant MeSH Terms: Glucose Metabolism Disorders; Metabolic Diseases; Hyperglycemia
• Other Study ID Numbers: Pro00115197

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No