Many people with diabetes are aware that stress and illness can cause blood sugar fluctuations, but did you know changes in temperatures can affect blood sugar levels and lead to false readings? Sabrina Rene, M.D., an endocrinologist, explains how temperature can produce blood sugar highs and lows and how they can affect diabetes testing supplies.

Effects of warm weather on diabetics

During warmer months, it is especially important for people with diabetes to stay properly hydrated. Dehydration can cause blood sugar to rise as the glucose in your blood becomes more concentrated.

High temperatures can also cause blood vessels to dilate, which can enhance insulin absorption and potentially lead to low blood sugar. If you have diabetes, it is best to stay indoors during the hottest part of the day and monitor blood sugar closely for changes when temperatures start to rise.

Ideal storage temperature for diabetic testing supplies

Extreme heat and cold can affect insulin, test strips and glucose monitors. Never leave these supplies in a car, no matter what time of year.

The meter should also be stored and used in a room that remains between 50 and 104 degrees Fahrenheit. Dr. Rene says it is important to store test strips in a dry, cool place.

“You never want to store test strips in your bathroom. The warm, humid atmosphere can damage the strips, causing them to produce false readings,” she says.

Vascular problems and temperature changes

Patients with vascular problems often lack proper blood flow, especially to their extremities, and cold weather may exacerbate slow blood flow. Diabetes test strips need a certain level of oxygen and blood flow to calculate the glucose level accurately. The lower these are, the less accurate the reading, Dr. Rene says.

Raynaud’s phenomenon

People with diabetes also need to be aware of an autoimmune condition called Raynaud's phenomenon. Brought on by cold weather and stress, this condition causes numbness and coldness in the fingers and toes.

This usually occurs when blood vessels constrict in the hands and feet. It can lead to an abnormally low blood sugar reading, but it is not necessarily indicative of a person’s blood sugar level throughout the body.

Testing reminders

Dr. Rene recommends the following routine for testing at any time of the year:

• Wash your hands. This helps reduce the chance of infection at the injection site. Today’s blood sugar meters are highly sensitive, so proper hand-washing also ensures the test will not pick up any residue on your hands. If you do not have access to clean water, wipe the first drop of blood away with a clean tissue or piece of clothing and use the second drop of blood to help improve test accuracy.

• Dry your hands thoroughly. Extraneous fluids can affect test readings.

• Rub your hands together to create a warm area for testing.

“If you get a low reading, but don’t have symptoms that correspond with low blood sugar, like shaky hands, feeling warm or lightheadedness, go ahead and retest yourself to make sure you are getting an accurate reading. Listen to your body. How you feel can be a great indicator of your blood sugar level.”

Proper home testing is an important part of care for people with diabetes. If you are having trouble taking, reading or monitoring your glucose levels, make an appointment with your doctor. Properly managing diabetes is essential to good health.

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