Determining the Appropriate Intensity of Exercise to Prevent Post-exercise Hypoglycemia in Persons Living With T1D

Summary

Over 300, 000 youth and young adults across Canada are living with Type 1 Diabetes (T1D) which is considered the most common endocrine condition. Physical activity offers numerous health benefits however the majority of persons living with T1D are physically inactive, primarily due to fear of low blood sugar (hypoglycemia). This fear of hypoglycemia continues to exist for physically active persons with T1D as no established physical activity guidelines exist. Several acute studies have used high intensity interval training as a way to reduce the risk of hypoglycemia as it has the ability to activate fight or flight hormones which can raise blood sugar; however the intensity needed to elicit this response is unknown.

The purpose of this project is to determine the acute effects of varying exercise intensities on the time spent in a low blood sugar range in 10 sedentary (VIGOR acute sedentary) and 16 physically active (VIGOR acute trained) individuals with T1D. Each participant will complete a maximal exercise test prior to the exercise sessions. Sedentary participants will complete 45 minutes of continuous moderate intensity exercise at 45-55% heart rate reserve (HRR) and three high intensity interval sessions with six one minute burst of high intensity at 70%, 80%, or 90% of HRR every four minutes. Active participants will complete 45 minutes of moderate intensity exercise at 45-55% of HRR and one high intensity interval session at 90% of HRR with intervals spaced every two minutes.

The investigators will track the blood sugar response to exercise using a device called a continuous glucose monitor (CGM) which records blood sugar every five minutes over a period of six days. The CGM will help determine which exercise intensity does a better job at reducing the time spent in a low blood sugar range. The information gained through this study will help individuals with T1D remain active without fear of low blood sugar and provide guidelines for professionals working with this population.

Adding high intensity bursts at 80% and 90% of maximum aerobic capacity (active participants) or heart rate reserve (sedentary participants) to a moderate intensity exercise session will significantly reduce the amount of time spent in a low blood sugar range in sedentary and active persons with T1D compared to moderate intensity exercise alone.

Conditions

• Type 1 Diabetes

Interventions

OTHER

Exercise

The intervention will be the different high intensity sessions. Time spent in hypoglycemia and glucose variability will be compared as follows: 70% vs. moderate, 80% vs. moderate, and 90% vs. moderate to see if high intensity is protective against hypoglycemia and provides lower glucose variability levels.

Sponsors & Collaborators

• The Lawson Foundation

  collaborator OTHER

• University of Manitoba

  lead OTHER

Principal Investigators

• Jonathan McGavock, PhD · University of Manitoba; Children's Hospital Research Institute of Manitoba

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

15 Years

Max Age

35 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2013-05-31

Primary Completion

2016-03-31

Completion

2016-03-31

Countries

• Canada

Study Locations