Exercise and the Menstrual Cycle in Type 1 Diabetes

Effects of the Menstrual Cycle on Blood Glucose Changes During Exercise in Women With Type 1 Diabetes Using Oral Contraceptives

Female participants with type 1 diabetes using oral contraceptives will be asked to wear a continuous glucose monitor for at least three days on two separate occasions (once during the last week of active pills and once during the no pill/placebo pill phase of the menstrual cycle). An exercise session (45 minutes of aerobic exercise at 60% VO2peak on a cycle ergometer) will take place at 5 pm on the second day of glucose monitoring.

Study Overview

• Status: Recruiting
• Conditions: Type 1 Diabetes
• Intervention / Treatment: Behavioral: Luteal Phase Aerobic Exercise; Behavioral: Follicular Phase Aerobic Exercise

Detailed Description

Pre-test measures: Interested participants will be invited to the Physical Activity and Diabetes Laboratory on the main campus of the University of Alberta. They will be asked questions related to their menstrual cycle, physical activity levels and medication. Blood pressure will also be measured to assess their eligibility. Where participants are eligible, anthropometric characteristics will be measured using standard protocols. A blood sample will be drawn for assessment of HbA1c. Participants will perform an incremental treadmill test to volitional exhaustion. Indirect calorimetry will be used to assess oxygen consumption and carbon dioxide production to determine the participant's aerobic capacity.

Testing sessions: Participants will perform two testing sessions separated by at least 5 days. One session will take place during the last week of active pill consumption of monophasic hormonal contraceptives. The second session will take place during the placebo pill consumption phase (i.e. menses). Participants will be asked to arrive at the lab at around 4:00 pm for both sessions, which will be randomly assigned. During the sessions, participants will be asked to perform 45 minutes of aerobic exercise on an ergonomic cycle ergometer at 60% of the participant's pre-determined aerobic capacity. Blood samples will be drawn at baseline, at the end of exercise, and an hour post-exercise via an IV catheter. 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. They will also be asked to avoid strenuous exercise and alcohol intake.

A continuous glucose monitor (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 in the morning of the day prior to each testing session. The participant will wear the CGM for at least 24 hours before the exercise session, and at least 24 hours after the exercise session.

• Study Type: Interventional
• Enrollment (Estimated): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Alberta
    • Edmonton, Alberta, Canada, T6G 2R3
      • Recruiting
      • Alberta Diabetes Institute
      • Contact: Jane E Yardley, PhD; Phone Number: 7806791688; Email: jane.yardley@ualberta.ca

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• type 1 diabetes diagnosed for at least 1 year
• regular menses
• using monophasic oral contraceptives
• residing in Edmonton, Alberta and able to visit the lab at the University of Alberta

Exclusion Criteria:

• HbA1c > 9.9%
• frequent and unpredictable hypoglycemia
• change in insulin management strategy within two months of the study
• use of an automated insulin delivery system
• blood pressure > 140/95
• history of cardiovascular disease
• severe peripheral neuropathy
• active proliferative retinopathy
• use of medications (other than insulin) that would affect blood glucose levels
• any musculoskeletal condition that would contraindicate exercise (e.g. sprain, strain, joint injury, etc.)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• 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 be in a single study arm.	Behavioral: Luteal Phase Aerobic Exercise; Participants will perform 45 minutes of moderate (60% VO2peak) aerobic exercise on a cycle ergometer during the last week of active pill consumption.; Behavioral: Follicular Phase Aerobic Exercise; Participants will perform 45 minutes of moderate (60% VO2peak) aerobic exercise on a cycle ergometer within 5 days of starting their menses.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood glucose	Change in blood glucose, with samples drawn via IV catheter	Pre-exercise (0 minutes), post-exercise (45 minutes) and 1 hour post-exercise

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Interstitial glucose (continuous glucose monitoring)	Mean CGM glucose	6 hours, 12 hours, overnight (midnight to 6 am) and 24 hours post-exercise
coefficient of variation (CV)	measure of variability for continuous glucose monitoring data	6 hours, 12 hours, overnight (midnight to 6 am) and 24 hours post-exercise
standard deviation (SD)	measure of variability for continuous glucose monitoring data	6 hours, 12 hours, overnight (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, 12 hours, overnight (midnight to 6 am) and 24 hours post-exercise
frequency of hyperglycemia	number of times that CMG glucose is equal to or greater than 10.0 mmol/L	6 hours, 12 hours, overnight (midnight to 6 am) and 24 hours post-exercise
percent of time in range	percent of time with CGM glucose between 4.0 and 9.9 mmol/L	6 hours, 12 hours, overnight (midnight to 6 am) and 24 hours post-exercise
percent of time in hypoglycemia	amount of time spent with CGM glucose equal to or less than 3.9 mmol/L	6 hours, 12 hours, overnight (midnight to 6 am) and 24 hours post-exercise
percent of time in hyperglycemia	amount of time spent with CGM glucose equal to or greater than 10.0 mmol/L	6 hours, 12 hours, overnight (midnight to 6 am) and 24 hours post-exercise

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Carbohydrate supplementation	Grams of carbohydrate provided to prevent hypoglycemia	Between 0 minutes and 45 minutes (during exercise)

Collaborators and Investigators

• Sponsor: University of Alberta
• Collaborators: Women and Children's Health Research Institute, Canada

Study record dates

Study Major Dates

• Study Start (Actual): March 15, 2022
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): August 30, 2026

Study Registration Dates

• First Submitted: December 8, 2021
• First Submitted That Met QC Criteria: January 10, 2022
• First Posted (Actual): January 12, 2022

Study Record Updates

• Last Update Posted (Estimated): July 8, 2025
• Last Update Submitted That Met QC Criteria: July 4, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Autoimmune Diseases; Immune System Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Diabetes Mellitus, Type 1
• Other Study ID Numbers: Pro0083867

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