Exercising in Hot Conditions: How Does it Effect Blood Glucose in People With T1D (T1D-Heat)

January 5, 2026 updated by: Liverpool John Moores University

The Effect of Acute Heat Exposure on Glucose Use During Moderate-intensity Exercise in People With Type 1 Diabetes

A randomised, crossover, counterbalanced repeated measures study will be conducted to examine the effect of acute heat exposure on rate of change in blood glucose concentration during 40 minutes of moderate-intensity exercise and for 30 minutes after exercise. Participants will complete two experimental conditions during two separate laboratory visits, with the order of conditions randomised. One condition will be a temperate condition of 20°C with 50% relative humidity (Temperate), the other will be 40°C with 50% relative humidity (Heat). Visits will be identical, including time of day, except for the condition. Visits will be separated by 24h. Testing will take place in the laboratories of the Research Institute for Sport and Exercise Sciences at Liverpool John Moores University.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
38

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United Kingdom
      • Liverpool, United Kingdom, L33AF
        • Recruiting
        • Liverpool John Moores University
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • T1D diagnosis more than 1 years ago (to ensure participants are out of the honeymoon period)

  • Using insulin therapy with multiple daily injections (MDI), insulin pump (pump), or hybrid closed-loop (HCL)

    o If using a HCL system have experience of using a pre-programmed basal rate in manual mode during exercise

  • Aged 18-65 years
  • Regularly engaged in endurance exercise (training at least twice per week for ≥30 minutes per session)

Exclusion Criteria:

  • Pregnancy
  • <6 months postpartum or stopped breastfeeding <1 month before recruitment
  • Existing cerebrovascular or cardiovascular disease
  • Significant history of hyperglycaemia (HbA1c >85 mmol/mol)
  • History of severe hypoglycaemia requiring third party assistance within the last 3 months
  • Body weight <36.5kg
  • Difficulty swallowing tablets
  • Appointment for an MRI test that cannot be rescheduled
  • Obstructive gastrointestinal disease
  • History of gastrointestinal surgery
  • Have an implanted medical device

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Active Comparator: Temperate
40 minutes of moderate intensity continuous exercise at 20°C with 50% relative humidity
Behavioral: Exercise
exercise in the heat or temperate conditions
Experimental: Heat
40 minutes of moderate intensity continuous exercise at 40°C with 50% relative humidity
Behavioral: Exercise
exercise in the heat or temperate conditions

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
blood glucose
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in blood glucose concentration
Baseline pre exercise to end of exercise (40 minutes)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Core temperature
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in core temperature
Baseline pre exercise to end of exercise (40 minutes)
Skin temperature
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in skin temperature
Baseline pre exercise to end of exercise (40 minutes)
Free fatty acids
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change free fatty acid concentration
Baseline pre exercise to end of exercise (40 minutes)
insulin
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
Change in insulin concentration
Baseline pre exercise to end of exercise (40 minutes)
glucagon
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in glucagon concentration
Baseline pre exercise to end of exercise (40 minutes)
epinephrine
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in epinephrine concentration
Baseline pre exercise to end of exercise (40 minutes)
norepinephrine
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in norepinephrine concentration
Baseline pre exercise to end of exercise (40 minutes)
cortisol
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in cortisol concentration
Baseline pre exercise to end of exercise (40 minutes)
Growth hormone
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in Growth hormone concentration
Baseline pre exercise to end of exercise (40 minutes)
lactate
Time Frame: Baseline pre exercise to end of exercise (40 minutes)
change in lactate concentration
Baseline pre exercise to end of exercise (40 minutes)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Liverpool John Moores University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 1, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 25, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 5, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 14, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 14, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 5, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 25/SPS/065

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

On request to PI

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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