Heat and Type 1 Diabetes


Note: This article is part of our Daily Life library of resources. To learn more about the many things that affect your health and daily management of type 1, visit here.

Whether experiencing hot summer temperatures or a tropical vacation, it is important for everyone to beware of the heat—and the various effects that it can have on our bodies. Have you ever noticed your blood sugar either spiking or dropping rapidly in severe temperatures? Many people with type 1 diabetes run into this issue and have been baffled as to why. Heat may have much more of an impact on your blood glucose levels than you realized! Keeping a close eye on your blood glucose (BG) becomes even more important when in areas with higher temperatures.

Here are some possible explanations to the heat’s role in blood sugar fluctuations, and some factors to keep in mind while enjoying your summer fun in the sun with type 1!

High blood sugar

Heat can spike blood sugar levels easily if we are not properly hydrated. When the body is dehydrated, blood glucose becomes more concentrated due to the decrease in blood flow through the kidneys. This makes it much more difficult for the kidneys to remove any excess glucose from urine.

How to fix it? Adjust insulin dosages as instructed by a medical professional, and most importantly drink plenty of water!

Low blood sugar

Blood glucose levels have been known to plummet in the heat—especially when combined with exercise. Why is this?

Heat can cause the body’s blood vessels to expand, which in turn can speed up insulin absorption and potentially lead to hypoglycemia. This can be made worse when exercising due to the increased blood flow to certain areas, especially if insulin is injected in the legs. Also consider that hot tubs/jacuzzis or hot showers/baths can have the same affect, leading to hypoglycemia.

Dry heat vs. humidity

It is important to stay hydrated and closely monitor BG levels in both humid and dry weather. However, sweat evaporates more easily in dry heat allowing the body to naturally cool itself, whereas in humidity sweat evaporates very slowly. Due to variables such as the heat index, the heat feels exaggerated in humid climates.

All beverages are not created equal

Water is always the best option to keep yourself hydrated in high temperatures, but drinks such as non-caffeinated iced herbal teas are effective as well.

Drinks that act as diuretics or that have a high caffeine or sodium content can actually dehydrate you (which could lead to BG malfunctions!)

Some examples are:

  • Alcohol
  • Sodas and most energy drinks
  • Coffee
  • Milk
  • Caffeinated tea

Sports drinks such as Gatorade can be effective, but beware of the high sugar content and perhaps reserve those carb heavy drinks for a low blood sugar.

Similar symptoms

The symptoms of heat exhaustion and hypoglycemia (low blood sugar) can feel very similar! It is important to check your BG levels even if you think that you are simply feeling the effects of the heat.

Symptoms of both scenarios can include:

  • Sweating
  • Shakiness
  • Dizziness
  • Lethargy
  • Blurred vision
  • Hunger
  • Irritability

Heat can tamper with medications

If insulin is exposed to extreme heat for too long, it will become ineffective, which would certainly cause blood sugar spikes! The heat can also alter the effectiveness of supplies such as test strips and BG meters. Be sure to check the labels on all of your supplies for specific temperature requirements.

Read Cold Weather and Type 1 DiabetesNavigating the BBQ with Type 1 Diabetes and Your Type 1 Guide to Music Festivals.

WRITTEN BY BT1 Editorial Team, POSTED 06/23/16, UPDATED 12/22/22

This piece was authored collaboratively by the Beyond Type 1 Editorial Team.