NCT07491133

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.

Trial Health

63
Monitor

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
30

participants targeted

Target at below P25 for not_applicable

Timeline
13mo left

Started Mar 2026

Geographic Reach
1 country

1 active site

Status
not yet recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress17%
Mar 2026Jul 2027

Study Start

First participant enrolled

March 1, 2026

Completed
17 days until next milestone

First Submitted

Initial submission to the registry

March 18, 2026

Completed
6 days until next milestone

First Posted

Study publicly available on registry

March 24, 2026

Completed
11 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

March 1, 2027

Expected
4 months until next milestone

Study Completion

Last participant's last visit for all outcomes

July 1, 2027

Last Updated

March 24, 2026

Status Verified

March 1, 2026

Enrollment Period

1 year

First QC Date

March 18, 2026

Last Update Submit

March 18, 2026

Conditions

Type 1 Diabetes Mellitus

Keywords

Type 1 diabetesInsulin absorptionTemperature exposureBlood glucoseContinuous glucose monitoringHypoglycemia

Outcome Measures

Primary Outcomes (1)

  • Change in plasma glucose concentration during temperature 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.

    Measured at baseline, 60 minutes, and 120 minutes during each 2-hour environmental chamber exposure.

Secondary Outcomes (5)

  • Change in plasma insulin concentration during temperature exposure

    Measured at baseline, 60 minutes, and 120 minutes during each 2-hour environmental chamber exposure.

  • 24-hour time in glucose range

    24 hours before and 24 hours after each temperature exposure visit.

  • 24-hour time above glucose range

    24 hours before and 24 hours after each temperature exposure visit.

  • 24-hour time below glucose range

    24 hours before and 24 hours after each temperature exposure visit.

  • Continuous glucose monitor accuracy

    During each 2-hour temperature exposure.

Study Arms (3)

Cold exposure

EXPERIMENTAL

Participants will be exposed to cold temperature (10°C/50°F) in an environmental chamber for 120 minutes while seated. This temperature is designed to induce shivering thermogenesis and increase energy expenditure by approximately 80%. The cold exposure may slow insulin absorption from subcutaneous injection sites due to reduced skin blood flow and vasoconstriction. Participants will wear standard clothing (shorts and t-shirt) with optional socks and gloves if needed for comfort. Continuous monitoring includes core body temperature via rectal probe, skin temperature at four sites, heart rate, blood pressure every 10 minutes, and blood glucose via continuous glucose monitor every 15 minutes. Blood samples will be collected at baseline, 60 minutes, and 120 minutes for plasma glucose, insulin, glucagon, and metabolic markers. The exposure will be terminated if core body temperature drops to ≤35.5°C.

Other: Environmental Temperature Exposure

Neutral Temperature

ACTIVE COMPARATOR

Participants will be exposed to neutral room temperature (23°C/73°F) in an environmental chamber for 120 minutes while seated. This condition serves as the control/reference temperature representing typical indoor environmental conditions. At this temperature, normal thermoregulatory responses are minimal, allowing assessment of baseline insulin absorption and glucose responses without temperature-induced physiological stress. Participants will wear standard clothing (shorts and t-shirt) and undergo the same monitoring protocol as other arms: continuous core and skin temperature measurement, heart rate monitoring, blood pressure every 10 minutes, blood glucose monitoring every 15 minutes via continuous glucose monitor, and blood sampling at baseline, 60 minutes, and 120 minutes.

Other: Environmental Temperature Exposure

Hot/Humid Exposure

EXPERIMENTAL

Participants will be exposed to hot and humid conditions (36°C/97°F with 65% relative humidity) in an environmental chamber for 120 minutes while seated. These conditions simulate a hot summer day in Montreal and are designed to increase skin blood flow through vasodilation, potentially accelerating insulin absorption from subcutaneous depot sites. The combination of heat and humidity will induce thermal stress and sweating responses. Participants will wear standard clothing (shorts and t-shirt) with access to water as needed. The same comprehensive monitoring protocol applies: continuous measurement of core body temperature, skin temperature at four body sites, heart rate, blood pressure every 10 minutes, and blood glucose every 15 minutes. Blood samples will be collected at baseline, 60 minutes, and 120 minutes. The exposure will be terminated if core body temperature reaches ≥39.5°C.

Other: Environmental Temperature Exposure

Interventions

Environmental Temperature ExposureOTHER

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.

Also known as: Temperature Stress Testing, Thermal Exposure Protocol, Environmental Chamber Study, Ambient Temperature Intervention, Temperature-Insulin Absorption Study
Cold exposureHot/Humid ExposureNeutral Temperature

Eligibility Criteria

Age18 Years - 45 Years
Sexall
Healthy VolunteersNo
Age GroupsAdult (18-64)

You may qualify if:

  • Diagnosis of type 1 diabetes for more than 2 years
  • Ability to provide verbal and written informed consent
  • Ability to speak and understand French

You may not qualify if:

  • Recent and/or unstable health condition (less than 3 months) prior to enrolment
  • Any viral infection at time of participation
  • Chronic illness other than type 1 diabetes (for example: pulmonary disease, cardiovascular disease, cancer)
  • Health condition not controlled by medication
  • Pregnancy or breastfeeding (for female participants)
  • Any other health condition deemed to pose undue health risks during participation in the study

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Institut de recherches cliniques de Montréal

Montreal, Quebec, H2W 1R7, Canada

Location

Related Publications (18)

  • Stapleton JM, Yardley JE, Boulay P, Sigal RJ, Kenny GP. Whole-body heat loss during exercise in the heat is not impaired in type 1 diabetes. Med Sci Sports Exerc. 2013 Sep;45(9):1656-64. doi: 10.1249/MSS.0b013e31829002f3.

    PMID: 23475170BACKGROUND

  • Wolf, S.T., Havenith, G., Kenney, W.L., 2023. Relatively minor influence of individual characteristics on critical wet-bulb globe temperature (WBGT) limits during light activity in young adults (PSU HEAT Project). Journal of Applied Physiology 134, 1216-1223. https://doi.org/10.1152/japplphysiol.00657.2022

    BACKGROUND

  • Taylor, N.A.S., 2014. Human heat adaptation. Compr Physiol 4, 325-365. https://doi.org/10.1002/cphy.c130022

    BACKGROUND

  • Singh, N., Areal, A.T., Breitner, S., Zhang, S., Agewall, S., Schikowski, T. and Schneider, A., 2024. Heat and cardiovascular mortality: an epidemiological perspective. Circulation research, 134(9), pp.1098-1112.

    BACKGROUND

  • Robine, J.-M., Cheung, S.L.K., Le Roy, S., Van Oyen, H., Griffiths, C., Michel, J.-P., Herrmann, F.R., 2008. Death toll exceeded 70,000 in Europe during the summer of 2003. C R Biol 331, 171-178. https://doi.org/10.1016/j.crvi.2007.12.001

    BACKGROUND

  • Ratter-Rieck, J.M., Roden, M. and Herder, C., 2023. Diabetes and climate change: current evidence and implications for people with diabetes, clinicians and policy stakeholders. Diabetologia, 66(6), pp.1003-1015.

    BACKGROUND

  • Nakaji, S., Parodi, S., Fontana, V., Umeda, T., Suzuki, K., Sakamoto, J., Fukuda, S., Wada, S. and Sugawara, K., 2004. Seasonal changes in mortality rates from main causes of death in Japan. European journal of epidemiology, 19, pp.905-913.

    BACKGROUND

  • Masselot, P., Mistry, M., Vanoli, J., Schneider, R., Iungman, T., Garcia-Leon, D., Ciscar, J.C., Feyen, L., Orru, H., Urban, A. and Breitner, S., 2023. Excess mortality attributed to heat and cold: a health impact assessment study in 854 cities in Europe. The Lancet Planetary Health, 7(4), pp.e271-e281.

    BACKGROUND

  • Information CIfH, 2020. Drug use among seniors in Canada.

    BACKGROUND

  • Gasparrini A, Guo Y, Sera F, Vicedo-Cabrera AM, Huber V, Tong S, de Sousa Zanotti Stagliorio Coelho M, Nascimento Saldiva PH, Lavigne E, Matus Correa P, Valdes Ortega N, Kan H, Osorio S, Kysely J, Urban A, Jaakkola JJK, Ryti NRI, Pascal M, Goodman PG, Zeka A, Michelozzi P, Scortichini M, Hashizume M, Honda Y, Hurtado-Diaz M, Cesar Cruz J, Seposo X, Kim H, Tobias A, Iniguez C, Forsberg B, Astrom DO, Ragettli MS, Guo YL, Wu CF, Zanobetti A, Schwartz J, Bell ML, Dang TN, Van DD, Heaviside C, Vardoulakis S, Hajat S, Haines A, Armstrong B. Projections of temperature-related excess mortality under climate change scenarios. Lancet Planet Health. 2017 Dec;1(9):e360-e367. doi: 10.1016/S2542-5196(17)30156-0.

    PMID: 29276803BACKGROUND

  • Gasparrini, A., Guo, Y., Hashizume, M., Lavigne, E., Zanobetti, A., Schwartz, J., Tobias, A., Tong, S., Rocklöv, J., Forsberg, B., Leone, M., De Sario, M., Bell, M.L., Guo, Y.-L.L., Wu, C., Kan, H., Yi, S.-M., de Sousa Zanotti Stagliorio Coelho, M., Saldiva, P.H.N., Honda, Y., Kim, H., Armstrong, B., 2015. Mortality risk attributable to high and low ambient temperature: a multicountry observational study. Lancet 386, 369-375. https://doi.org/10.1016/S0140-6736(14)62114-0

    BACKGROUND

  • Gallo, E., Quijal-Zamorano, M., Méndez Turrubiates, R.F., Tonne, C., Basagaña, X., Achebak, H. and Ballester, J., 2024. Heat-related mortality in Europe during 2023 and the role of adaptation in protecting health. Nature medicine, pp.1-5.

    BACKGROUND

  • Damiano, E.R., El-Khatib, F.H., Zheng, H., Nathan, D.M. and Russell, S.J., 2013. A comparative effectiveness analysis of three continuous glucose monitors. Diabetes Care, 36(2), pp.251-259.

    BACKGROUND

  • Costello, A., Abbas, M., Allen, A., Ball, S., Bell, S., Bellamy, R., Friel, S., Groce, N., Johnson, A., Kett, M., Lee, M., Levy, C., Maslin, M., McCoy, D., McGuire, B., Montgomery, H., Napier, D., Pagel, C., Patel, J., de Oliveira, J.A.P., Redclift, N., Rees, H., Rogger, D., Scott, J., Stephenson, J., Twigg, J., Wolff, J., Patterson, C., 2009. Managing the health effects of climate change: Lancet and University College London Institute for Global Health Commission. Lancet 373, 1693-1733. https://doi.org/10.1016/S0140-6736(09)60935-1

    BACKGROUND

  • Carter, M.R., McGinn, R., Barrera-Ramirez, J., Sigal, R.J. and Kenny, G.P., 2014. Impairments in local heat loss in type 1 diabetes during exercise in the heat. Medicine and science in sports and exercise, 46(12), pp.2224-2233.

    BACKGROUND

  • Bitton, G., Rom, V., Hadelsberg, U., Raz, I., Cengiz, E., Weinzimer, S. and Tamborlane, W.V., 2019. Effect of injection site cooling and warming on insulin glargine pharmacokinetics and pharmacodynamics. Journal of Diabetes Science and Technology, 13(6), pp.1123-1128.

    BACKGROUND

  • Ballester, J., Quijal-Zamorano, M., Méndez Turrubiates, R.F., Pegenaute, F., Herrmann, F.R., Robine, J.M., Basagaña, X., Tonne, C., Antó, J.M., Achebak, H., 2023. Heat-related mortality in Europe during the summer of 2022. Nat Med 29, 1857-1866. https://doi.org/10.1038/s41591-023-02419-z

    BACKGROUND

  • Battelino T, Alexander CM, Amiel SA, Arreaza-Rubin G, Beck RW, Bergenstal RM, Buckingham BA, Carroll J, Ceriello A, Chow E, Choudhary P, Close K, Danne T, Dutta S, Gabbay R, Garg S, Heverly J, Hirsch IB, Kader T, Kenney J, Kovatchev B, Laffel L, Maahs D, Mathieu C, Mauricio D, Nimri R, Nishimura R, Scharf M, Del Prato S, Renard E, Rosenstock J, Saboo B, Ueki K, Umpierrez GE, Weinzimer SA, Phillip M. Continuous glucose monitoring and metrics for clinical trials: an international consensus statement. Lancet Diabetes Endocrinol. 2023 Jan;11(1):42-57. doi: 10.1016/S2213-8587(22)00319-9. Epub 2022 Dec 6.

    PMID: 36493795BACKGROUND

MeSH Terms

Conditions

Diabetes Mellitus, Type 1Hypoglycemia

Condition Hierarchy (Ancestors)

Diabetes MellitusGlucose Metabolism DisordersMetabolic DiseasesNutritional and Metabolic DiseasesEndocrine System DiseasesAutoimmune DiseasesImmune System Diseases

Central Study Contacts

Corinne Suppere, MSc

CONTACT

514-987-5597corinne.suppere@ircm.qc.ca

Jane Yardley, PhD

CONTACT

514-987-5568jane.yardley@ircm.qc.ca

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
TREATMENT
Intervention Model
CROSSOVER
Model Details: This is a randomized crossover study where all 30 participants will experience three temperature conditions (cold 10°C, neutral 23°C, and hot/humid 36°C) in random order. Each participant serves as their own control, completing all three 2-hour environmental chamber exposures separated by at least 3 days. During each visit, participants remain seated while researchers continuously monitor blood glucose, body temperature, heart rate, and blood pressure, with blood samples collected at baseline, 60 minutes, and 120 minutes. The crossover design eliminates individual variability in diabetes management and insulin sensitivity, allowing precise detection of temperature effects on insulin absorption and glucose control.
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

March 18, 2026

First Posted

March 24, 2026

Study Start

March 1, 2026

Primary Completion (Estimated)

March 1, 2027

Study Completion (Estimated)

July 1, 2027

Last Updated

March 24, 2026

Record last verified: 2026-03

Data Sharing

IPD Sharing
Will not share

Locations

CA(1)