June 2026
People with type 1 and type 2 diabetes tend to be more affected by summer heat than people without diabetes, according to the U.S. Centers for Disease Control and Prevention (CDC).
Here are three summer heat problems that tend to be exacerbated in people with diabetes — and concrete steps you can use to help prevent them.
Dehydration
People with diabetes become dehydrated more quickly. When blood sugar is high, the body pulls more water into the urine to remove excess sugar. That can lead to dehydration. Dehydration can also raise blood sugar, which may increase urination even more. It’s a vicious cycle!
In addition, some commonly used medications — including “water pills” used to treat high blood pressure — can increase fluid loss and raise the risk of dehydration.
To prevent this problem, people with diabetes need to be especially careful to stay properly hydrated. The National Academy of Medicine’s general guidelines for adults are at least 13 cups of fluid per day for men and 9 cups per day for women. If you’re physically active or it’s hot out, you may need more.
Here are four ways to prevent dehydration:
- Try these hydration tips to ensure you’re getting enough fluid each day.
- Avoid or strictly limit alcohol and drinks with caffeine, such as coffee and energy drinks. Caffeine and alcohol act as diuretics, meaning that they cause your body to excrete more fluid, increasing your risk of dehydration.
- Keep your blood sugar under control. This will limit excessive fluid loss due to high blood sugar.
- Follow the tips below to avoid heat exhaustion and heat stroke. Staying cooler and out of the sun will help minimize excessive fluid loss due to heat.
Heat exhaustion and heat stroke
Some diabetes complications, such as nerve and blood vessel damage, can impair your ability to sweat. This means your body can’t cool as effectively as it should, increasing your risk of heat exhaustion and heat stroke.
Managing your blood sugar can help minimize diabetes complications, such as nerve damage, over time. You also need to take extra precautions to protect against heat exhaustion and heat stroke. In addition to drinking more, you should also:
- Stay inside in air-conditioning when it’s hottest.
- Wear loose, lightweight, light-colored clothing.
- Seek shade if you’re outside in the heat and use clothing and a wide-brimmed hat to keep the sun off your skin. (Direct sunlight can increase your risk of heat-related illness.)
- Know the heat index — the “feels like” temperature, which takes into account both the temperature and the humidity. When it’s humid, the heat will affect you more because the humidity makes it harder for your body to cool off by sweating.
- Get medical attention if you experience symptoms of heat-related illness, such as headaches, dizziness, nausea, shortness of breath, muscle cramping, and excessive sweating.
Changes to the way the body uses insulin
Hot weather can affect how your body uses insulin. On the one hand, higher temperatures can increase blood flow to your skin (one way your body tries to cool off). This can cause injected insulin to be absorbed faster than usual, increasing your risk of low blood sugar.
On the other hand, hot weather can trigger your body to release stress hormones like cortisol. Any kind of stress (emotional or physical) can make your body more insulin-resistant, raising your blood sugar.
Here’s how to minimize potential problems:
- Test your blood sugar more often than usual (especially if you’re exercising in the heat). Alternatively, ask your doctor if a continuous glucose monitor (CGM) is right for you.
- Ask your doctor to help you build a plan for when — and how often — to test your blood sugar during extreme heat. Your healthcare provider can also help you plan how to adjust your insulin and eating habits if you notice heat-related changes.
- Keep snacks handy in case your blood sugar falls unexpectedly.
- Wear sunscreen (SPF 15 or higher), a hat, and other protective clothing when you’re outside, especially if the forecasted UV Index will be high.
