Effect of Ambient Temperature on Blood Glucose and Insulin Absorption in Adults With Type 1 Diabetes

Condition(s) studied

Investigational drug(s) / intervention(s)

Environmental Temperature Exposure: Systematic exposure to controlled temperature and humidity conditions in a specialized environmental chamber. Each exposure lasts 120 minutes with participants remaining seated throughout. All exposures include standardized pre-exposure preparation (60-minute baseline period at room temperature), continuous physiological monitoring, standardized clothing, and identical blood sampling schedules. Safety protocols include continuous staff supervision, predetermined stopping criteria for extreme body temperatures or blood pressure changes, and immediate availability of warming/cooling interventions and hypoglycemia treatment protocols.

Study summary

The goal of this clinical trial is to learn how different temperatures affect blood sugar levels in adults with type 1 diabetes. Climate change is causing more extreme hot and cold weather, and people with type 1 diabetes may be at higher risk during these temperature changes. The main questions it aims to answer are:

* Do different temperatures (cold, normal, or hot) change blood sugar levels in people with type 1 diabetes?
* How does temperature affect insulin absorption in the body?

Researchers will compare three different temperature conditions to see how each affects blood sugar levels and insulin in the body.

Participants will:

* Complete a screening visit with body measurements and questionnaires
* Attend 3 separate study visits, each in a different temperature setting:
* Cold room (10°C/50°F)
* Normal room temperature (23°C/73°F)
* Hot and humid room (36°C/97°F with 65% humidity)
* Sit for 2 hours in each temperature condition while researchers monitor their blood sugar, heart rate, and body temperature
* Wear a continuous glucose monitor for 48-72 hours before each visit
* Keep a diary of food, sleep, and activity for 24 hours before and after each visit

Each temperature visit is separated by at least 3 days. The study helps researchers understand if people with type 1 diabetes need special guidance for managing their blood sugar during extreme weather.

Eligibility

Primary outcome measure(s)

• Change in plasma glucose concentration during temperature exposure — Measured at baseline, 60 minutes, and 120 minutes during each 2-hour environmental chamber exposure.
  The primary outcome is the change in plasma glucose levels (mmol/L) from baseline to end of exposure across the three temperature conditions (cold 10°C, neutral 23°C, hot/humid 36°C). Blood samples will be collected via intravenous catheter and analyzed for plasma glucose concentration. This measure will assess whether ambient temperature affects blood glucose control in individuals with type 1 diabetes, with the hypothesis that cold exposure may increase glucose levels due to slower insulin absorption, while heat exposure may decrease glucose levels due to faster insulin absorption.

Trial sites (1)

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