Hot weather can affect your diabetes

It may come as a surprise to some or perhaps you’ve already experienced it, but the weather can influence your diabetes, including your blood glucose levels. Yes, it’s something else to consider! With the weather heating up, we thought it a good time to cover this topic and offer some tips to help manage the heat.

Our body works best when body systems and organs are functioning in normal ranges, including our blood glucose levels (BGLs). Other examples include the amount of oxygen and carbon dioxide in our lungs and the pH levels of our stomach and bloodstream. Keeping a steady temperature or thermal regulation is just as important.

Our body has built-in systems to counteract external changes in temperature and help maintain the ideal body temperature, such as shivering when it’s cold or sweating when it’s hot.

Some of these responses may not work as well for people living with diabetes and might make you more vulnerable during extreme hot weather.  Let’s explore some of the common ways heat can affect diabetes.

Heat exhaustion

The body’s normal response to a hot environment is to increase blood vessels size to allow more blood flow to the skin. Special nerves then stimulate our skin to sweat.[i]  It is the evaporation of this sweat off the skin that begins to cool us down.

People living with diabetes may find it more difficult to sweat due to changes in hormones or nerve damage, making it harder to stay cool.[i] This can increase the risk of heat exhaustion and is especially important to consider for those with circulation and nerve issues or those who are older.


In hotter weather we require extra fluid to ensure we remain hydrated. If someone living with diabetes becomes dehydrated this can raise BGLs due to the blood becoming more concentrated with glucose. As we get older we are more at risk of dehydration for a few reasons. The body is unable to store as much water, kidneys may not work as well as they used to, and we can even have a decreased perception of our thirst[ii].


Some people with diabetes may even notice they seem to experience more hypoglycaemia (hypos) in warmer weather. This may occur for various reasons.

Firstly, the body’s metabolism is higher in humid, hot weather as it is trying to cool us down.[iii] [iv]  This can then make blood vessels dilate and possibly enhance the absorption of insulin when injected.

Secondly, hot weather can decrease people’s appetite and therefore means less food may be eaten compared to normal.

Thirdly, we know hormones such as cortisol, glucagon and adrenaline usually increase in response to heat, keeping BGLs stable if they start dropping. For people living with diabetes, these responses may not work as well, increasing the risk of BGLs dropping in hot conditions.[iv]

Lastly, if someone exercises in the heat, this may increase the risk of a hypo due to the compounding reasons discussed above. This is especially important to consider if someone is either taking insulin or a class of medication called sulfonylureas.

Heat exhaustion or hypo?

Another important point to mention is that the signs and symptoms of a hypo can feel very similar to heat exhaustion.[4] Both may have symptoms such as sweating, dizziness, blurry vision, shakiness, hunger or irritability. It is important to regularly check BGLs if you are experiencing any of these symptoms. [v]

Storing medications, testing equipment

If not stored correctly the hotter weather can damage the quality and potency of insulin and blood glucose monitoring equipment. Insulin breaks down and loses potency much faster than usual when it’s exposed to heat, light or agitation[iv]. Test strips can be damaged by heat, humidity and light when stored incorrectly. Glucometers and pumps may also be affected by the heat. If these important tools are not working accurately it may have negative or even dangerous consequences when managing your diabetes.

Tips to beat the heat

As you can see, hotter weather can impact your diabetes management in many ways. Here is a list of the main tips to follow when we soon hit those scorching days:

  • Stay hydrated, even if you don’t feel thirsty.
  • Keep out of the heat of the day, especially if you’re about to exercise.
  • Check your BGLs more frequently, especially when not feeling well.
  • Wear lose fitted and light clothing and protect your skin with sunscreen. Sunburn will raise your BGLs.
  • Use or stay in air-conditioning when possible. Often a room fan isn’t enough on stifling days.
  • Safely store all equipment and medications out of heat.
  • Always wear shoes to protect your feet.
  • Have a backup plan for storing insulin in the storm season should the power go out.
  • Above all, contact your GP, Diabetes Educator or diabetes specialist if you have any concerns about points raised in this article.

By Linda Uhr

Accredited Practising Dietitian and Diabetes Educator



[i] Kenny, G. P., Sigal, R. J., & McGinn, R. (2016). Body temperature regulation in diabetes. Temperature (Austin, Tex.), 3(1), 119–145.

[ii] Dunning, T. (2014). Care of people with diabetes a manual of nursing practice (4th ed). Wiley Blackwell.

[iii] Tsujimoto, T., Yamamoto-Honda, R., Kajio, H., Kishimoto, M., Noto, H., Hachiya, R., Kimura, A., Kakei, M., & Noda, M. (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, 93(23), e148.

[iv] Westphal, S., Childs, R., Seifert, K., Boyle, M., Fowke, M., Iñiguez, P., & Cook, C. (2010). Managing Diabetes in the Heat: Potential Issues and Concerns. Endocrine Practice, 16(3), 506–511. doi:10.4158/ep09344.ra

[v] NSW Government. (2016). Heat-related illness.

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