How to Manage Your Diabetes in Extreme Summer Heat

How weather can affect your blood sugar
summer heat temperatures

By: Marwan Hamaty, MD

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We often look forward to changes of season, but if you have diabetes, you need to be extra careful when temperatures climb dramatically. Extreme heat can affect your blood sugar control.

If you use insulin or if your treatment of blood sugars is inadequate, this can put you at higher risk. Often, worsening blood sugar control is the main concern. Depending on the situation and your level of physical activity, low blood sugars are also possible.

Extreme temperatures can also damage your medications and testing equipment. I always remind my patients to take precautions to protect themselves and their supplies during both winter and summer.

If a patient’s blood sugars are mostly higher than 250 mg/dl, I recommend improving blood sugar control before engaging in heavy physical activity — regardless of the climate and the temperature, as recommended by the American Diabetes Association.

How heat can affect you

The extreme heat of summer affects blood sugar levels. How the heat affects your levels depends on what you’ve eaten, whether you’re well-hydrated and your activity level.

If the heat and your activity make you sweat profusely, you may become dehydrated, leading to a rise in glucose levels.

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If you become dehydrated, your blood glucose levels will rise. This can lead to frequent urination, which then leads to further dehydration and even higher blood sugar levels — a kind of vicious cycle.

Further, if the treatment includes insulin, dehydration reduces blood supply to the skin and, therefore, less absorption of injected insulin dosage.

Adjusting your insulin dosage

Most types of insulin can tolerate temperatures from 93 degrees F to 95 degrees F, but any higher than that and the medication will degrade rapidly. Attention should be paid to the insulin you are carrying along.

Physical activity is usually associated with reduced need for insulin. The latter may increase the risk for low blood sugars. Therefore, patient with diabetes in extreme weather conditions are at risk for both low and high blood sugars.

I advise my patients to maintain warm skin and adjust insulin dosage prior to engaging in physical activity. Insulin adjustment could vary significantly among patients. Seek individual advice from your doctor regardless of the temperature.

High temperatures can have an adverse effect on medication and other diabetes management supplies too. While it’s fine to store insulin and glucagon in the refrigerator, hot temperatures as well as freezing temperatures will cause the medications to degrade, making them ineffective and unusable.

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Don’t forget about the weather’s effect on things like test strips and monitoring devices. When exposed to extreme temperatures, the efficacy of these items begins to diminish.

Tips for managing blood sugar

Don’t allow the heat to keep you indoors. I tell my patients they can participate in outdoor activities and enjoy all types of weather as long as they take a few precautions.

Follow these tips to help manage your diabetes while enjoying the outdoors:

  1. Drink plenty of water. Staying hydrated is important for all people during physical activity, but it’s especially critical for people with diabetes. Avoid this by carrying small bottles of water or electrolyte replenishing sports drinks in a backpack or on a belt while hiking or engaging in sports.
  2. Make insulin adjustments as needed. Ask your provider and diabetes educator how you should adjust insulin prior to exercising. Typically, discussion during the first few visits focuses on urgent issues, such as getting diabetes under control. Ask about insulin adjustments so you can prepared for exercise.
  3. Test your blood sugars levels frequently. Since very hot temperatures can cause levels to fluctuate, it’s a good idea to test more frequently than usual. That way you can take appropriate and immediate action to keep levels more stable. Frequent monitoring should extend for several hours after the end of physical activity; the effects of activities on blood sugars usually last for a longer period of time.
  4. Keep items to treat low blood sugars with you. This includes glucose tabs or glucose gel. If you are at high risk for very low blood sugars (if you have frequent low blood sugar or had very low blood sugar previously), you should also have a glucagon kit available.
  5. Take some snack with you. Some snacks can serve as a meal replacement. Others can serve as ways to prevent low blood sugars. Discuss with your nutritionist possible options.
  6. Protect your medication and supplies. Take proactive steps to protect your insulin, glucagon kit and other supplies before you head outdoors, regardless of the temperature. Many of my patients have car coolers that plug into the 12-volt car adapter to keep their supplies at the proper temperature. This will keep the temperature stable for some time, but if you’re going away from your car for an extended period, you’ll need to take your supplies along with you. Be sure to protect your insulin pump from high temperature. Depending on the situation and duration of activity, the intervention could be as simple as monitoring glucose more often. In certain circumstances (very high temperature, longer duration of exposure), consideration could be given for temporary use of a long acting insulin along with meal insulin injection instead of insulin pump.
  7. Avoid sunburn. You can get sunburned while skiing on the slopes or while hiking in the summer. Sunburn stresses your body and can raise blood sugar levels. Use a broad spectrum sunscreen and wear protective eye gear.

Finally, use common sense when engaging in activities outdoors. While I don’t advise locking yourself inside during the peak winter or summer months, I also tell my patients to try to take time outdoors when temperatures aren’t too extreme. By taking a few precautions, you can enjoy an active, healthy lifestyle in most any weather.

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