Sometimes Diabetes Can’t Take the Heat

It’s summer for those of us in the Northern Hemisphere, and with the new season comes the usual increase in temperature. Add climate change and the continuing rise in temperature on our planet into the mix, and it creates some very concerning risks for people with diabetes and other chronic conditions. These risks are even more concerning for more vulnerable populations with diabetes, such as children, elderly, and people without access to cooler temperate environments.

Heat Exposure and Hospitalization for People with Diabetes

Given that this is something that we will not be able to avoid in the near future, figuring out how to reduce risks and manage heat exposure is important. There are more studies looking at the effects of heat on people with diabetes published in the last few years, and some have even been collecting data since 2000.

Here are some important data points from two recently published studies:

1. People with diabetes (of any type) tend to be more sensitive to extreme temperatures and are less able to regulate body temperature compared to people without diabetes¹
2. Short-term heat exposure can increase the risk of death due to diabetes.¹
3. In moderate to high-intensity heat waves in Brisbane, Australia, there was an increase in both hospitalizations for diabetes and post-discharge deaths.²
4. The risks of hospitalization and poor outcomes are higher for elderly and children with diabetes since they are more vulnerable.¹

Insulin in the Heat

After learning how to give injections, one of the first things you learn is how to store your insulin to keep it from getting too hot or too cold. If this does happen, the insulin will either not work as well or not work at all. It’s unfortunately not always apparent that the insulin has gone bad until you see unexplained high blood sugars, and by that point you probably are not feeling well.³

Insulin manufacturers have recommended storage temperatures listed on their website and on the inserts that come in the insulin box. They usually recommend storing unopened insulin in the fridge, and that you can keep opened insulin that you are using for 30-45 days, depending on the insulin.³ But what about when your available storage temperature is warmer than the recommended manufacturers’ storage? In many places around the world, access to air conditioning or refrigeration is not always an option.

Luckily, according to a study published in 2021, the commercial insulin manufacturers’ recommendations are conservative, and most insulins remain usable with more variability in temperature.⁴ These researchers studied the effects of higher and changing temperatures on the potency of the insulin and have found that it can usually last around four weeks in the conditions that were studied – from 25 – 37 degrees Celsius (77 – 98.6 degrees Fahrenheit).⁴ The study also suggested that exposure to higher temperatures, even if for a short time, caused more of a loss of potency of the insulin than below the temperature of 37 degrees Celsius.

How to Take Extra Care in the Heat

These studies are meant to help people take extra caution when exposed to higher temperatures as a person with diabetes.

Here are some tips for keeping yourself safe:

• Stay hydrated! Water and drinks that have electrolytes are best.¹
• Keep your insulin as cool as you can – indoors with air conditioning if you have it, in a cooler (not directly on ice), in a Frio pack or something like it.³
• Check your blood sugar more often and make sure you are adjusting insulin as needed.
• If you’re at the beach and disconnected from your insulin pump, make sure you reconnect and take your missed basal every 60-90 minutes.
• Be sure to avoid putting your insulin in direct sunlight – and hiding it under a towel does not count as shade!³
• Check for ketones if your blood sugars are high, if you feel dehydrated, or if you’re worried at all – and treat accordingly.

All of these tips are probably helpful for those of you attending our upcoming Friends for Life conference in Orlando in two weeks. And for everyone else, hopefully this helps you enjoy your summer without letting diabetes get in the way!

1. Association between Heat Exposure and Hospitalization for Diabetes in Brazil during 2000–2015: A Nationwide Case-Crossover Study
2. Heatwaves and diabetes in Brisbane, Australia: a population-based retrospective cohort study
3. Insulin Temperature Control: What You Need to Know
4. Heat-stability study of various insulin types in tropical temperature conditions: New insights towards improving diabetes care

Written and clinically reviewed by Marissa Town, RN, BSN, CDCES