Tips to Prevent Heat-Related Illness

Summertime! While many of us relish the heat after a cold winter, excessive heat can be dangerous. Between the years 1979-2003, excessive heat caused over 8,000 deaths in the United States. More people died from extreme heat than from hurricanes, lightning, tornadoes, floods, and earthquakes combined.

Doctors have discovered that people with diabetes are at a greater risk of adverse effects from heat. Other conditions related to risk include age, obesity, dehydration, heart disease, poor circulation, sunburn, and prescription drug and alcohol use. However, even young and healthy individuals can succumb to heat if they participate in strenuous physical activities during hot weather.Unfortunately, many diabetics don’t prepare for extreme heat situations which place them at a higher risk for death.

“Studies have shown that during heat waves, patients with diabetes have more hospitalizations, more emergency room visits, and higher rates of mortality,” says Curtiss B. Cook MD, FACP, professor of medicine at the Mayo Clinic College of Medicine and a consultant in endocrinology at the Mayo Clinic in Arizona. “Why that is isn’t clear, but it does show that these people are at greater risk for health problems during hot weather.”

The body normally cools itself by sweating. But under some conditions, sweating just isn’t enough. According to Dr. Adrienne Nassar, researcher at the Mayo Clinic, “People with diabetes have an impaired ability to sweat, which predisposes them to heat-related illness, as do uncontrolled, high blood sugars.”

Dr. Nassar is the lead author of a study done at the Phoenix Diabetes Clinic, where 152 patients were surveyed to determine their awareness of how weather could affect their diabetes.

One in five survey respondents reported that they do not take precautions until temperatures exceed 100 degrees Fahrenheit. “Heat illness can take place at 80 to 90 degrees when you factor in the heat index,” Nassar said. About 50% of patients could define heat index, which is a combination of air temperature and humidity. The danger with high humidity is that it slows the evaporation of perspiration, interfering with the body’s ability to cool itself.

The National Weather Service suggest that diabetics and others at a higher risk for heat sensitivity should begin taking precautions when the heat index reaches 80 or 90 to avoid heat stroke and other heat-related conditions.

Summertime activity, whether working outdoors or recreating, must be balanced with measures that aid the body’s cooling mechanisms and prevent heat-related illness.

KIDD - girl drinking waterHow to Prevent Heat Related Illnesses

  • Air-conditioning is the number one protective factor against heat-related illness and death. Stay indoors and, if at all possible, stay in an air-conditioned place. If your home does not have air conditioning, go to the shopping mall or public library. Even a few hours spent in air conditioning can help your body stay cooler when you go back into the heat. Call your local health department to see if there are any heat-relief shelters in your area.
  • Drink more fluids (nonalcoholic), regardless of your activity level. Don’t wait until you’re thirsty to drink. Many diabetics are known to have suboptimal glycemic condition, which may increase a diabetic’s risk of dehydration. Many people with diabetes may also have a diminished thirst reflex, and may not stay adequately hydrated, further increasing the risk for heat-induced illness.
  • Warning: If your doctor generally limits the amount of fluid you drink or has you on water pills, ask him how much you should drink when the weather is hot.
  • Don’t drink liquids that contain alcohol, caffeine or large amounts of sugar. These types of drinks actually cause you to lose more body fluid.
  • Avoid very cold drinks, because they can cause stomach cramps.
  • Electric fans may provide comfort, but when the temperature is in the high 90s, fans will not prevent heat-related illness. Taking a cool shower or bath, or moving to an air-conditioned place is a much better way to cool off.
  • Wear lightweight, light-colored, loose-fitting clothing.
  • NEVER leave anyone in a closed, parked vehicle.
  • Use your stove and oven less to maintain a cooler temperature in your home.
  • Avoid hot foods and heavy meals—they add heat to your body.

Hot Weather and Diabetes Medications

Heat can also interfere with the performance of diabetes medications and supplies. Extreme temperature changes can have an effect on your diabetes supplies; insulin can break down, blood glucose meters and test strips can be damaged, and altitude can affect blood glucose meter performance.

“Oral medications as well as insulin have a therapeutic temperature range above which they lose efficacy,” Nassar said. The drug insert provides information regarding proper storage temperatures.

Blood glucose monitoring strips contain enzymes that measure glucose levels, and those enzymes can be damaged with extreme heat. “There’s no way to tell, just by looking at a strip, whether it’s been damaged by heat, so a patient may not know they shouldn’t use it,” says Cook. If someone does use a damaged strip, the glucose levels it indicates will be all over the place, he added.

While 73% of participants in the Phoenix study acknowledged receiving information about the harmful effects of heat on insulin, only 39% recalled information on the adverse effects of heat on oral diabetes medications. 41% knew about the effects of heat on glucose meters, and 38% recalled the effects on glucose test strips.

Among those who know that heat is harmful to their medications and glucose-testing supplies, 37% chose to leave them at home to avoid the risk of heat exposure. But that creates added risk.

“If they are unable to check their blood sugars while they are away from home, that’s unsafe,” Nassar said.

“Increasingly more people with diabetes are living in places characterized by hot weather. Patient education focusing on diabetes management in hot climates is needed,” Nassar concluded.

People with diabetes should be vigilant with glucose testing and control during periods of extreme heat.

If you must be out in the heat

  • Be aware that any sudden change in temperature, such as an early summer heat wave, will be stressful to your body. You will have a greater tolerance for heat if you limit your physical activity until you become accustomed to the heat. If you travel to a hotter climate, allow several days to become acclimated before attempting any vigorous exercise, and work up to it gradually.
  • Limit your outdoor activity to morning and evening hours when temperatures are cooler.
  • If you must exercise, consider water sports such as swimming or paddling or an area with plenty of tree cover/shade. You can also exercise in an air conditioned facility or early in the morning or well after sunset.
  • According to the National Athletic Trainers’ Association, it’s possible to become dehydrated to the point of heat illness in as little as an hour of exercise. Athletes can reach this level even more rapidly if they begin the workout, practice or competition dehydrated. Drink two to four glasses of cool, nonalcoholic fluids each hour.
  • Recognize the early warning signs of dehydration. These can include: dark yellow urine, loss of energy, dizziness, loss of coordination, cramps, headaches, or unusual fatigue. If left untreated, more extreme symptoms can occur.
  • Sports beverage can replace the salt and minerals you lose in sweat but look for those low in sugar. Warning: If you are on a low-salt diet, talk with your doctor before drinking a sports beverage.
  • Increase the frequency and duration of rest breaks to help you stay hydrated and cool. Rest often shady areas.
  • Protect yourself from the sun by wearing a hat with a wide brim or visor. Wear sunglasses with UV protection and always wear sunscreen of SPF 15 or higher.
  • When working in the heat, monitor the condition of your co-workers and have someone do the same for you. Heat-induced illness can cause a person to become confused or lose consciousness.

Heat related illness

One other note: be good to your pets in hot weather and be sure to provide plenty of fresh water for your pets, and leave the water in a shady area. – See more at:
One other note: be good to your pets in hot weather and be sure to provide plenty of fresh water for your pets, and leave the water in a shady area. – See more at:
One other note: be good to your pets in hot weather and be sure to provide plenty of fresh water for your pets, and leave the water in a shady area. – See more at:


Canadian Medical Association Journal (2009, August 26). Heat Stress In Older People And People With Chronic Diseases. ScienceDaily.

Centers for Disease Control and Prevention

The Endocrine Society (2010, June 21). Many people with diabetes do not know or heed dangers of hot weather. ScienceDaily.

Mayo Clinic

NCEH’s Health Studies Branch