Ignite Creation Date:
2026-03-26 @ 3:19 PM
Ignite Modification Date:
2026-03-31 @ 12:39 PM
Study NCT ID:
NCT07491133
Status:
NOT_YET_RECRUITING
Last Update Posted:
2026-03-24
First Post:
2026-03-18
Is NOT Gene Therapy:
True
Has Adverse Events:
False
Brief Title:
Effect of Ambient Temperature on Blood Glucose and Insulin Absorption in Adults With Type 1 Diabetes
Sponsor:
Institut de Recherches Cliniques de Montreal
Organization:
Study Overview
Official Title:
Effect of Ambient Temperature on Insulin Absorption and Change in Blood Glucose Levels in Individuals With Type 1 Diabetes
Status:
NOT_YET_RECRUITING
Status Verified Date:
2026-03
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
T1Temp
Brief 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.
* 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.
Detailed Description:
Background and Rationale
Climate change is increasing the frequency of extreme weather events, including heat waves and cold snaps. People with type 1 diabetes face higher risks of illness and death during these extreme temperature periods compared to people without diabetes. However, the reasons for this increased risk are not well understood.
When insulin is injected under the skin, it forms a small reservoir from which it gradually enters the bloodstream. Temperature may affect how quickly this insulin is absorbed. Warmer temperatures increase blood flow to the skin, which could speed up insulin absorption and potentially cause blood sugar to drop too low (hypoglycemia). Colder temperatures might slow insulin absorption, leading to higher blood sugar levels (hyperglycemia).
Previous research from the 1980s showed that heating or cooling the injection site affects insulin absorption, but these studies were conducted before modern rapid-acting insulins and diabetes technologies like insulin pumps and continuous glucose monitors were available. No recent studies have examined how whole-body temperature exposure affects insulin absorption and blood sugar control in people with type 1 diabetes.
Study Design Overview
This is a randomized, crossover clinical trial where each participant will experience all three temperature conditions in random order. The study includes:
* 1 preliminary visit for screening and measurements
* 3 experimental visits (cold, neutral, hot conditions)
* Total participation time: approximately 14 hours over up to 4 months
Study Population
The study will enroll 30 adults aged 18-45 years with type 1 diabetes for at least 2 years. Participants will be equally divided by:
* Sex: 50% male, 50% female
* Insulin delivery method: 10 using multiple daily injections, 10 using insulin pumps, 10 using hybrid closed-loop systems
Preliminary Visit Procedures
During the first visit at the Montreal Clinical Research Institute (IRCM), participants will:
* Review and sign informed consent documents
* Complete medical history and lifestyle questionnaires
* Fill out a heat exposure questionnaire based on Health Canada guidelines
* Complete the GENESIS PRAXY questionnaire to document gender-related factors
* Undergo body measurements including height, weight, waist circumference, and body composition scan
* Have resting heart rate and blood pressure measured
* Receive training on continuous glucose monitor use (if not already using one)
Experimental Visit Procedures
Each of the three experimental visits will take place at Centre ÉPIC and follow the same protocol in different temperature conditions:
Pre-Exposure Phase (60 minutes)
* Participants arrive 2 hours after eating a standardized snack (100g Greek yogurt) with their usual insulin dose
* Body weight measurement
* Installation of rectal temperature probe (self-inserted privately)
* Placement of intravenous catheter for blood sampling
* Attachment of skin temperature sensors, blood pressure cuff, and heart rate monitor
* 60-minute rest period at room temperature to establish baseline measurements
Temperature Exposure Phase (120 minutes)
Participants will sit in an environmental chamber set to one of three conditions:
* Cold: 10°C (50°F) - causes shivering and increases energy expenditure by approximately 80%
* Neutral: 23°C (73°F) - comfortable room temperature
* Hot/Humid: 36°C (97°F) with 65% humidity - simulates a hot summer day in Montreal
Measurements During Exposure
Continuous monitoring:
* Heart rate via chest strap monitor
* Core body temperature via rectal probe
* Skin temperature at four sites (arm, chest, thigh, calf)
* Blood sugar levels via continuous glucose monitor (checked every 15 minutes)
Intermittent measurements:
* Blood pressure every 10 minutes
* Blood samples at baseline, 60 minutes, and 120 minutes for analysis of glucose, insulin, glucagon, and other metabolic markers
* Comfort and sensation ratings every 10 minutes using visual scales for thermal comfort, thermal sensation, and thirst
Safety Monitoring
Throughout each visit, research staff will continuously monitor participants for:
* Signs of hypoglycemia (low blood sugar) - treated immediately with glucose if needed
* Core body temperature limits (stopped if ≤35.5°C during cold or ≥39.5°C during heat exposure)
* Blood pressure limits (stopped if \>180/110 mmHg or \<90/60 mmHg)
* Participant comfort and willingness to continue
Data Collection
24-Hour Activity Logs
Participants will record their food intake, insulin doses, sleep patterns, and physical activity for:
* 48 hours before the preliminary visit (baseline lifestyle)
* 24 hours before each experimental visit
* 24 hours after each experimental visit
Continuous Glucose Monitoring
A Dexcom G7 sensor will be installed 48-72 hours before each visit to capture:
* Glucose patterns during temperature exposure
* 24-hour glucose control before and after each visit
* Time spent in target range (3.9-10.0 mmol/L)
* Time spent above target (\>10.0 mmol/L)
* Time spent below target (\<3.9 mmol/L)
Laboratory Analyses
Blood samples will be analyzed for:
* Plasma glucose and insulin levels
* Glucagon (hormone that raises blood sugar)
* Free fatty acids and glycerol (markers of fat metabolism)
* Other metabolic hormones
Special Considerations
For Female Participants Study visits will be scheduled during the follicular phase of the menstrual cycle (or placebo pill phase for those using oral contraceptives) since hormonal changes can affect blood sugar levels.
Insulin Delivery Methods The study will examine whether different insulin delivery methods (injections, pumps, or automated systems) respond differently to temperature changes.
Participant Safety and Comfort
* At least two research staff members will be present during each visit
* One staff member will remain in the environmental chamber with the participant
* Participants can request to stop the exposure at any time
* Emergency procedures are in place for severe blood sugar episodes
* Socks and gloves will be provided during cold exposure if needed
Study Significance
This research will provide the first modern evidence about how environmental temperature affects insulin absorption and blood sugar control in people with type 1 diabetes. The findings could lead to new clinical guidelines for diabetes management during extreme weather events, potentially reducing the increased health risks that people with type 1 diabetes face during heat waves and cold snaps.
The study results may inform recommendations for insulin dose adjustments during temperature extremes and help health care providers better advise patients with type 1 diabetes about managing their condition during increasingly frequent extreme weather events related to climate change.
Climate change is increasing the frequency of extreme weather events, including heat waves and cold snaps. People with type 1 diabetes face higher risks of illness and death during these extreme temperature periods compared to people without diabetes. However, the reasons for this increased risk are not well understood.
When insulin is injected under the skin, it forms a small reservoir from which it gradually enters the bloodstream. Temperature may affect how quickly this insulin is absorbed. Warmer temperatures increase blood flow to the skin, which could speed up insulin absorption and potentially cause blood sugar to drop too low (hypoglycemia). Colder temperatures might slow insulin absorption, leading to higher blood sugar levels (hyperglycemia).
Previous research from the 1980s showed that heating or cooling the injection site affects insulin absorption, but these studies were conducted before modern rapid-acting insulins and diabetes technologies like insulin pumps and continuous glucose monitors were available. No recent studies have examined how whole-body temperature exposure affects insulin absorption and blood sugar control in people with type 1 diabetes.
Study Design Overview
This is a randomized, crossover clinical trial where each participant will experience all three temperature conditions in random order. The study includes:
* 1 preliminary visit for screening and measurements
* 3 experimental visits (cold, neutral, hot conditions)
* Total participation time: approximately 14 hours over up to 4 months
Study Population
The study will enroll 30 adults aged 18-45 years with type 1 diabetes for at least 2 years. Participants will be equally divided by:
* Sex: 50% male, 50% female
* Insulin delivery method: 10 using multiple daily injections, 10 using insulin pumps, 10 using hybrid closed-loop systems
Preliminary Visit Procedures
During the first visit at the Montreal Clinical Research Institute (IRCM), participants will:
* Review and sign informed consent documents
* Complete medical history and lifestyle questionnaires
* Fill out a heat exposure questionnaire based on Health Canada guidelines
* Complete the GENESIS PRAXY questionnaire to document gender-related factors
* Undergo body measurements including height, weight, waist circumference, and body composition scan
* Have resting heart rate and blood pressure measured
* Receive training on continuous glucose monitor use (if not already using one)
Experimental Visit Procedures
Each of the three experimental visits will take place at Centre ÉPIC and follow the same protocol in different temperature conditions:
Pre-Exposure Phase (60 minutes)
* Participants arrive 2 hours after eating a standardized snack (100g Greek yogurt) with their usual insulin dose
* Body weight measurement
* Installation of rectal temperature probe (self-inserted privately)
* Placement of intravenous catheter for blood sampling
* Attachment of skin temperature sensors, blood pressure cuff, and heart rate monitor
* 60-minute rest period at room temperature to establish baseline measurements
Temperature Exposure Phase (120 minutes)
Participants will sit in an environmental chamber set to one of three conditions:
* Cold: 10°C (50°F) - causes shivering and increases energy expenditure by approximately 80%
* Neutral: 23°C (73°F) - comfortable room temperature
* Hot/Humid: 36°C (97°F) with 65% humidity - simulates a hot summer day in Montreal
Measurements During Exposure
Continuous monitoring:
* Heart rate via chest strap monitor
* Core body temperature via rectal probe
* Skin temperature at four sites (arm, chest, thigh, calf)
* Blood sugar levels via continuous glucose monitor (checked every 15 minutes)
Intermittent measurements:
* Blood pressure every 10 minutes
* Blood samples at baseline, 60 minutes, and 120 minutes for analysis of glucose, insulin, glucagon, and other metabolic markers
* Comfort and sensation ratings every 10 minutes using visual scales for thermal comfort, thermal sensation, and thirst
Safety Monitoring
Throughout each visit, research staff will continuously monitor participants for:
* Signs of hypoglycemia (low blood sugar) - treated immediately with glucose if needed
* Core body temperature limits (stopped if ≤35.5°C during cold or ≥39.5°C during heat exposure)
* Blood pressure limits (stopped if \>180/110 mmHg or \<90/60 mmHg)
* Participant comfort and willingness to continue
Data Collection
24-Hour Activity Logs
Participants will record their food intake, insulin doses, sleep patterns, and physical activity for:
* 48 hours before the preliminary visit (baseline lifestyle)
* 24 hours before each experimental visit
* 24 hours after each experimental visit
Continuous Glucose Monitoring
A Dexcom G7 sensor will be installed 48-72 hours before each visit to capture:
* Glucose patterns during temperature exposure
* 24-hour glucose control before and after each visit
* Time spent in target range (3.9-10.0 mmol/L)
* Time spent above target (\>10.0 mmol/L)
* Time spent below target (\<3.9 mmol/L)
Laboratory Analyses
Blood samples will be analyzed for:
* Plasma glucose and insulin levels
* Glucagon (hormone that raises blood sugar)
* Free fatty acids and glycerol (markers of fat metabolism)
* Other metabolic hormones
Special Considerations
For Female Participants Study visits will be scheduled during the follicular phase of the menstrual cycle (or placebo pill phase for those using oral contraceptives) since hormonal changes can affect blood sugar levels.
Insulin Delivery Methods The study will examine whether different insulin delivery methods (injections, pumps, or automated systems) respond differently to temperature changes.
Participant Safety and Comfort
* At least two research staff members will be present during each visit
* One staff member will remain in the environmental chamber with the participant
* Participants can request to stop the exposure at any time
* Emergency procedures are in place for severe blood sugar episodes
* Socks and gloves will be provided during cold exposure if needed
Study Significance
This research will provide the first modern evidence about how environmental temperature affects insulin absorption and blood sugar control in people with type 1 diabetes. The findings could lead to new clinical guidelines for diabetes management during extreme weather events, potentially reducing the increased health risks that people with type 1 diabetes face during heat waves and cold snaps.
The study results may inform recommendations for insulin dose adjustments during temperature extremes and help health care providers better advise patients with type 1 diabetes about managing their condition during increasingly frequent extreme weather events related to climate change.
Study Oversight
Has Oversight DMC:
False
Is a FDA Regulated Drug?:
False
Is a FDA Regulated Device?:
False
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?: