Rising Temperatures Linked to Hypoglycemia in Type 1 Diabetes, Suggests Research
UK: New research suggests that higher temperatures may significantly increase the short-term risk of hypoglycemia in adults with type 1 diabetes (T1D). The findings highlight the need for greater awareness and careful glucose monitoring during periods of hot weather.
The study, published in Diabetes Care, was conducted by Harriet E. Daultrey, Department of Global Health and Infection, Brighton and Sussex Medical School, Brighton, U.K., and colleagues. Researchers investigated whether changes in outdoor temperature were associated with short-term changes in the risk of hypoglycemia among adults living with T1D.
For the analysis, researchers used a case time series approach and examined routine continuous glucose monitoring (CGM) data from individuals with T1D. Hypoglycemia was defined as glucose levels below 3.9 mmol/L for at least 15 minutes. Statistical models accounted for factors including long-term trends, seasonal changes, day of the week, and public holidays.
The study included 32,966,282 glucose readings from 679 adults with T1D who attended two National Health Service clinics in Sussex, England, between 2017 and 2024.
The following were the key findings:
- Hypoglycemia risk increased nonlinearly when ambient temperatures exceeded 13°C.
- At 25°C, the odds of hypoglycemia reached 1.26.
- The strongest effect occurred on the same day as heat exposure and declined over subsequent days.
- Higher temperatures were also associated with lower mean daily glucose levels.
The researchers noted that several mechanisms could potentially contribute to the association, although the study did not directly assess insulin dosing or behavioral responses to heat. The findings suggest that people with T1D may require closer glucose monitoring and clinically guided insulin adjustments during hotter weather.
The study had several limitations. Residential postcodes were used to estimate temperature exposure, which may not accurately reflect the temperatures individuals actually experienced while indoors, working, or traveling. In addition, insulin dosing information was unavailable, limiting assessment of how treatment adjustments may have influenced glucose levels.
The researchers also cautioned that the findings may not apply to populations living in different climates or with different ethnic compositions. The study population was from southeast England, where recorded temperatures ranged from −3.7°C to 28.7°C.
The authors concluded that rising temperatures may increase the short-term risk of hypoglycemia in adults with T1D, particularly during periods of higher heat. They suggested that ambient temperature could be considered when guiding insulin adjustments, developing structured diabetes education, and potentially refining hybrid closed-loop insulin-delivery algorithms.
Reference:
Harriet E. Daultrey, Nick S. Oliver, Ali J. Chakera, Arturo de la Cruz Libardi, Collins C. Iwuji, Antonio Gasparrini; The Association Between Ambient Temperature and Hypoglycemia in People Living With Type 1 Diabetes: A Case Time Series Analysis Using Real-Time Continuous Glucose Monitoring. Diabetes Care 20 July 2026; 49 (8): 1323–1329. https://doi.org/10.2337/dc25-2383
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