How Heat Affects Your Body When You Have Diabetes: What to Know and How to Stay Safe in Hot Weather 

When temperatures rise, everyone feels the heat. But if you’re living with diabetes, the hot weather can affect your body in different and sometimes more dangerous ways.  

Whether you’re enjoying a summer day outside or living in a warmer climate year-round, it’s important to understand how heat and diabetes interact so you can stay healthy and safe.  

Why Heat Impacts People with Diabetes Differently 

When it’s hot out, your body works hard to stay cool. You sweat more, your heart rate increases, and your blood vessels widen to help release heat. But when you have diabetes, these natural cooling systems might not work as well. 

The Center for Disease Control advises that if temperatures reach 80 degrees Fahrenheit in the shade with 40% humidity, it can bring the heat index up to 15 degrees higher in the sunshine. This can make it harder for the body to sweat and release heat normally when living with diabetes. 

Nerve damage (neuropathy) caused by diabetes can make it harder for your body to know when it’s getting too hot or to sweat properly. 

Sweat glands can be affected, as well. Decreasing the ability to cool the body temperature. This can lead to heat exhaustion, a condition that requires immediate medical attention. 

Dehydration happens faster, too. Dehydration or loss of body fluid due to high temperatures, usually causes high blood sugar causing an increase in urination. This means the loss of fluids in the body can occur quicker, due to high temperatures. 

Additionally, insulin and heat don’t mix well. Hot temperatures can change how your body absorbs insulin and can also damage insulin, test strips, and glucose sensors. When the body gets heated, it can dilate blood vessels and increase the absorption of insulin. High temperatures can increase blood glucose levels. Do not leave insulin, test strips, glucometers, insulin pumps, continuous glucose monitors/sensors in cars or locations that heat over 86 degrees Fahrenheit as that can destroy insulin’s function, accuracy of test strips and insulin pumps have an internal battery and they have been known to stop total functioning. If wearing an insulin pump, be aware the insulin in the pump is being exposed to the same high heat and may not work as well for the 2 to 3 days between pump site changes. This requires awareness of blood glucose levels and possible change in insulin before the usual routine with pump site changes. 

Blood sugar levels can swing up and down quickly. This can make managing diabetes more challenging and require talking to your doctor more often for support. This also requires testing blood glucose levels more often whether using a glucose meter or continuous glucose monitoring system.  

Signs of Overheating / Heat Exhaustion 

It’s easy to miss the signs of heat exhaustion or heat stroke if you’re not paying attention.  

These include heavy sweating, dizziness or weakness, headaches, nausea or vomiting, cool and clammy skin, fast or increased heartbeat. 

For heat exhaustion, keep an eye out for heavy sweating, dizziness or weakness, headaches, nausea or vomiting, cool, clammy skin and a fast or increasing heartbeat 

For signs of heat stroke, look for hot, dry skin (no sweating), confusion, slurred speech, very high body temperature, rapid breathing, and loss of consciousness. Some of these symptoms can also be similar to hypoglycemia. Please check blood sugar levels throughout the day and night.  Remember, heat stroke is considered a medical emergency. If you, or someone you know, experience any of these symptoms, call 911 immediately. 

Tips to Stay Cool and Safe 

You don’t have to avoid summer fun, but a little planning goes a long way when you have diabetes. Here are some helpful tips: 

• Hydrate, hydrate, hydrate! Drink water often, even if you’re not thirsty. Avoid drinks containing caffeine which can increase dehydration. Limit drinking sugary drinks drinking only when treating low blood sugar. Avoid alcohol, which can contribute to low blood sugar and dehydration. 

• Stay indoors during peak heat. If possible, stay indoors during peak heat. The hottest part of the day is usually between 10am to 4pm. If going outside during those times, make sure to wear sunscreen. Sun burn can occur easily and can affect blood sugar levels. If you can, do errands or exercise early in the morning or later in the evening. To get in daily exercise try walking indoors at malls or large grocery stores. 

• Dress smartly. Wear light-colored, loose clothing and a wide-brimmed hat to help your body stay cool. 

• Protect your meds and supplies. Insulin, test strips, cgm reader/receiver and sensors and insulin pumps can all be damaged when exposed to heat for a long period of time. Please do not leave supplies in a location, such as your car, for an extended period of time. If insulin is left in warm places for too long, it can damage the insulin. To the point that insulin does not work well. This can mean having to start a new insulin pen or vial or change out a cartridge/reservoir for an insulin pump, sooner than planned. Keep them in a cooler or insulated bag, but do not let them touch ice packs directly. 

• Check your blood sugar more often. Heat can make your blood sugar go up or down quickly. Test more frequently to catch any changes early. 

• Know your body. If you feel dizzy, tired, or just “off,” it might be more than the sun. Check your blood sugar and find some shade or air conditioning fast. 

Don’t Sweat It! You’ve Got This!  

Living with diabetes doesn’t mean you have to sit out in summer or avoid the sun. It just requires a little extra preparation. Heat affects your body in unique ways, but with the right steps, you can stay cool, stay safe, and still enjoy the warm weather. 

Author: Janet Dominowski, MS, RDN, CDCES | CCS Health      

This site is for educational purposes only. Talk to your doctor or healthcare provider before making any decisions about your health.