How Do Colder Temperatures Influence Blood Sugar Levels?

The winter solstice is almost here, and so are cold temperatures and the official beginning of winter. Did you ever think that outdoor temperatures influence your blood sugar levels? If you did, you were right: extreme temperatures can destabilize your blood sugar. Generally, blood sugar levels are lower in the summer and higher in colder temperatures.

Glycemic imbalance

Studies have found that the hemoglobin A1c of people living with type 1 diabetes is, on average, higher in winter than in summer. There are many likely causes:

  • A lot of people are more active in summer. In colder temperatures, physical inactivity increases insulin resistance, which in turn tends to increase blood sugar levels if insulin dosage is not adjusted properly. Maintaining some regular physical activity during winter could help to balance blood sugar levels. 
  • Winter is cold and flu season. Viral infections are known to increase blood sugar levels. If you are sick, be extra mindful of your blood sugar and make sure you measure your ketone bodies.
  • Colder temperatures slow down the bloodstream, which disrupts the distribution of insulin in the body.

A few tips

Take a walk, put on your ice skates or your skis, dust off your fat bike… and have fun! A number of indoor sports facilities are currently closed due to the COVID-19 pandemic, so it’s time to find something that you can do regularly and that will let you enjoy winter. Also, take a look at these training programs you can do at home, developed by the BETTER team. 

It is also recommended to monitor your blood sugar more closely during winter activities. Using a continuous or flash glucose monitoring system can help to keep your hands away from the cold. But keep in mind that, like any other electronic device, these tools’ performance can be impacted by very cold temperatures.   

If you plan to be outside for several hours and want to have your insulin with you, it’s very important that you keep it from freezing, as freezing and near-freezing temperatures destroy insulin molecules. That’s why you shouldn’t keep your insulin outside in a parked car or in your coat’s outer pocket.


  • Surviving winter with type 1 diabetes. (n.d.). Retrieved November 16, 2020, from https://www.jdrf.ca/blog/surviving-winter-with-type-1-diabetes/
  • Tsujimoto, T. et al. (2014). Seasonal variations of severe hypoglycemia in patients with type 1 diabetes mellitus, type 2 diabetes mellitus, and non-diabetes mellitus: clinical analysis of 578 hypoglycemia cases. Medicine.
  • Higgins, T., Saw, S., Sikaris, K., Wiley, C. L., Cembrowski, G. C., Lyon, A. W., . . . Tran, D. (2009). Seasonal Variation in Hemoglobin A1c: Is It the Same in Both Hemispheres? Journal of Diabetes Science and Technology, 3(4), 668-671. doi:10.1177/193229680900300408

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