How exercising in hot weather affects blood sugar in people with type 1 diabetes.

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

NA · Liverpool John Moores University · NCT07341243

This study will test whether 40 minutes of moderate exercise in hot conditions changes blood sugar during exercise and for 30 minutes afterward in adults with type 1 diabetes.

Quick facts

PhaseNA
Study typeInterventional
Enrollment38 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorLiverpool John Moores University (other)
Locations1 site (Liverpool)
Trial IDNCT07341243 on ClinicalTrials.gov

What this trial studies

This randomized, crossover, counterbalanced study has participants complete two laboratory visits performing 40 minutes of moderate-intensity exercise under either temperate (20°C, 50% humidity) or hot (40°C, 50% humidity) conditions. Visits are identical except for temperature, separated by 24 hours, and use continuous glucose monitoring to track blood glucose during exercise and for 30 minutes afterwards. Eligible adults aged 18–65 with type 1 diabetes for more than one year who regularly perform endurance exercise and use multiple daily injections, an insulin pump, or a hybrid closed-loop system will be enrolled. Testing takes place in the Research Institute for Sport and Exercise Sciences laboratories at Liverpool John Moores University.

Who should consider this trial

Good fit: Ideal candidates are adults 18–65 with type 1 diabetes diagnosed over one year ago, who regularly do endurance exercise (at least twice weekly for ≥30 minutes) and use MDI, an insulin pump, or a hybrid closed-loop system.

Not a fit: Patients with recent severe hypoglycaemia, significant cardiovascular or cerebrovascular disease, very high HbA1c (>85 mmol/mol), pregnancy, or those who do not regularly exercise are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, findings could help people with type 1 diabetes plan insulin and exercise strategies to reduce risky high or low blood sugars when exercising in hot weather.

How similar studies have performed: Prior studies suggest temperature can influence glucose responses to exercise, but direct evidence in adults with type 1 diabetes using controlled hot-condition protocols is limited.

Eligibility criteria

Show full inclusion / exclusion criteria
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

Where this trial is running

Liverpool

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Type 1 Diabetes, exercise, heat

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.