Dr. Marwan Hamaty, an endocrinologist at the Cleveland Clinic, explained the following when talking about how hot weather affects diabetes control.
Heat, especially extreme heat, can make it difficult for anyone to tolerate. It is especially difficult for people with diabetes. When the body is exposed to heat, people lose more water through sweat, which can lead to dehydration. Dehydration can increase blood sugar levels. High blood sugar can make urination more frequent, further exacerbating dehydration. To maintain a good hydration status, fluid intake must be increased. Patients can tell when they are taking in adequate fluids because the urine becomes lighter in color due to the increased amount of fluid in the body.
Heat affects the way the body absorbs insulin. In hot weather, more blood will flow to the skin. When dehydration sets in, the opposite happens – less blood goes to the skin. Most types of insulin, especially short-acting insulins, don’t work well when blood flow is reduced.
Heat can affect drug efficacy. If insulin is left in a hot car, it will begin to degrade. Bring a cooling device to keep the insulin at or below room temperature. Excessive temperatures can also damage the test strips and cause incorrect readings, which can affect blood glucose management and the amount of insulin injected.
Caution is especially needed when exercising in the heat. Watch out for hyperglycemia and hypoglycemia. If you are taking a medication that may cause hypoglycemia, your blood sugar may drop. Exercising outside in hot weather can cause similar symptoms, such as sweating and a faster heart rate, so it is extremely easy to overlook the early signs of hypoglycemia. This is why blood glucose testing needs to be done every hour or two while exercising. Carry juice, glucose tablets or glucose gel with you for exercise to prevent blood sugar levels from dropping. If injecting insulin, ask your doctor how to adjust the dose when exercising.
Avoid sunburn, which can damage your skin and interfere with diabetes control. Severe sunburn can cause inflammation, which in turn can raise blood sugar. Apply broad-spectrum sunscreen and wear protective clothing and a wide-brimmed hat when you go outside.
Finally, take good care of your feet. Avoid walking barefoot, especially if there is nerve damage, which can reduce the ability to feel sharp objects and hot surfaces. Patients may unconsciously cause injury to themselves. Wear protective footwear. Check the feet daily for cuts and other injuries. Also look for scaly rashes on the feet and white patches between the toes, which may be tinea pedis. Sweaty feet can make you more susceptible to tinea pedis and other fungal infections. Keep your feet dry and treat them with over-the-counter antifungal creams as soon as you notice ringworm.