Summer Heat Is a Risk to Diabetes Patients

Survey Shows Many People With Diabetes Aren't Protecting Themselves From High Temperatures

Medically Reviewed by Laura J. Martin, MD on June 22, 2010
From the WebMD Archives

June 22, 2010 -- People with diabetes can be extra sensitive to high temperatures, and many don't take enough precautions early enough, according to a new survey.

The results weren't all bad. "Most patients incorporated appropriate personal protective measures such as staying indoors, drinking additional fluids on schedule, applying sunscreen, and wearing protective clothing," says Adrienne A. Nassar, MD, a third year resident at Mayo Clinic Arizona, who presented the findings at ENDO 2010 in San Diego, the annual meeting of the Endocrine Society.

But the respondents fell short in other ways. For instance, one in five waited until temperatures were over 100 degrees before taking precautions, Nassar said at a news conference And 23% began drinking fluids when they got thirsty -- typically too late to prevent dehydration effectively. Many left their medications and monitoring equipment at home during a heat wave.

Nassar and her colleagues analyzed responses of 152 people with diabetes living in Phoenix, where the average July temperature is 107 F.

On average, the patients were 64 years old, 85% had type 2 diabetes, and 77% were on insulin injections or pumps. Their blood glucose test results on the hemoglobin A1c tests were on average 7.9%, although the goal for those with diabetes is 7%.

Survey Results

While many respondents protected their medication in the heat by carrying it in a cooler, 37% left medication or supplies at home.

"This is quite concerning,'' Nassar says, "because they would not have the means to check their blood sugar" if they became faint, for instance.

While most respondents, 72%, knew about the effect of heat on insulin, just 40% said they had gotten information from their health care providers about the ill effects of high temperature on oral medications, 41% on glucose monitors, and 38% on glucose monitoring strips.

The point at which respondents said they would take protective measures varies. Nassar can't pinpoint an exact temperature at which protective measures should begin since it depends not only on temperature but on such factors as humidity.

Only 55% of the survey respondents knew the definition of ''heat index," she found. Heat index is a measure of how hot it feels when the relative humidity is added to the air temperature. For instance, if the temperature is 108 F but the humidity is 45%, the heat index is 137 F.

According to the National Weather Service, those in high risk groups should begin taking precautions when the heat index reaches 80 or 90 to avoid heat stroke, sunstroke, and other problems.

Nassar found that 68% of respondents limited heat exposure to less than an hour, but that many people delayed protective measures too long. ''Overall, we found many patients expose themselves to high temperatures before taking protective measures," Nassar says.

Second Opinion

''This study addresses an interesting and timely question," says Ruchi Mathur, MD, an assistant professor of medicine at Cedars-Sinai Medical Center, Los Angeles, who reviewed the findings for WebMD.

She points out, however, that most of the respondents did not have well-controlled diabetes and so may not represent the general population of those with diabetes.

''This study does make us aware that further education is needed to provide patients with diabetes the information they need to tackle such extreme weather conditions safely," Mathur says. All patients with diabetes, not just those on insulin, need education about how to handle high temperatures and take care of medication -- whether they use injected insulin or oral medications, she says.

Nassar tells those with diabetes to follow simple steps in the heat to stay healthy, such as:

  • Pay attention to fluid intake before becoming thirsty (with specific instructions from your doctor).
  • Exercise in air-conditioning if possible or if outdoors, late in the evening or early morning when temperatures are lower.
  • Look at the package inserts for medication to determine safe storage temperatures.

Show Sources


Adrienne A. Nassar, MD, Mayo Clinic Arizona.

Ruchi Mathur, MD, assistant professor of medicine, Cedars-Sinai Medical Center, Los Angeles.

American Diabetes Association.

The Weather Channel.

ENDO 2010, 92nd annual meeting and expo, The Endocrine Society, San Diego, June 19-22, 2010.

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