Can Diabetes Affect Your Ability to Drive?

People with diabetes generally pose no greater safety risk while driving than the average driver who doesn’t have diabetes. Your ability to drive is generally affected if your diabetes is controlled by medications that lower blood sugar. This is primarily a concern for those who are on insulin and have a history of hypoglycemia, or low blood sugar. If your blood sugar is too low, you may experience symptoms or it may trigger a related condition that can affect your ability to drive.

Hypoglycemia

If you have low blood sugar, or hypoglycemia, it can cause:

• confusion
• a loss of consciousness
• blurred vision
• shakiness
• dizziness
• fainting
• fatigue
• lightheadedness

Researchers in a study of 452 drivers with type 1 diabetes asked participants to self-report any episodes of hypoglycemia over the course of one year. They also asked them to report whether these episodes impacted their driving.

Fifty-two percent of drivers reported at least one hypoglycemia-related incident while driving. They classified the following occurrences as incidents:

• getting into a collision
• receiving a ticket
• losing control of the vehicle
• relying on automatic driving
• requiring someone else to take over at the wheel
• otherwise losing the ability to drive

Five percent of participants reported six or more incidents.

Seizures

Researchers in a 2016 study found that people with type 1 diabetes are three times more likely to develop a seizure disorder such as epilepsy. This may relate back to complications such as hypoglycemia. Prolonged and repeated periods of hypoglycemia may damage your central nervous system. Whether this definitively increases your risk for seizures is still under investigation.

Neuropathy

Over time, people with diabetes can develop nerve damage throughout the body. This is called neuropathy. Although having high blood sugar can damage any nerve in the body, neuropathy generally affects your legs and feet first.

Many people experience mild pain, tingling, or numbness in the affected area. Others may experience more debilitating pain. This can pose a serious problem while driving.

You may be able to control your symptoms by managing your blood sugar or taking medication, though it’s possible to have a flare in symptoms.

Vision problems

Poorly controlled blood sugar can also affect your vision, both in the short and long term. In the short term, high blood sugar levels can cause fluid to shift into the eye and blurry vision.

In the long term, high blood sugar levels can damage blood vessels in the tissue that lines the back of the eye. This area is called the retina. Retinopathy is the most common cause of vision loss in people with diabetes.

If you have retinopathy, you may experience:

• blurred vision
• tunnel vision
• difficulty differentiating between colors

If your symptoms are uncontrolled, this change in vision can significantly impact your ability to drive.

Insulin use

If it’s necessary for you to use insulin, it may take time to consistently administer the correct dosage. Receiving too much or too little insulin can be dangerous and lead to extremely high or low blood sugar levels. Low blood sugar levels may cause symptoms such as a loss of consciousness, blurred vision, and dizziness.

Check out: Diabetes and blurry vision: What you need to know »

Each state’s department of motor vehicles has its own rules about obtaining a license if you have a preexisting medical condition. Some states apply the same rules to all drivers, regardless of whether they have a medical condition such as diabetes. Other states may only apply these rules to people with diabetes. Visit the American Diabetes Association to learn more about your state’s requirements.

Depending on the state, you may be required to self-report:

• whether you have diabetes
• whether you’ve experienced episodes of severe hypoglycemia
• the number of hypoglycemic episodes you’ve experienced
• any visual limitations
• what medications you take

If your state requires a medical evaluation, your doctor will assess your current condition and symptoms to determine whether it’s safe for you to drive. This documentation is required to complete your licensing application. If your doctor doesn’t believe you’re fit to drive, your application will be denied.

Always check your blood sugar level before getting into a car to drive, particularly if you’re taking insulin or other medications that increase insulin levels in the body. You shouldn’t start driving if your sugar level is under 70 to 90 milligrams per deciliter. If your blood sugar is lower than desired, you should take immediate action.

Depending on your doctor’s suggested care plan, this may mean eating a sugary snack, drinking juice or soda, or taking a glucose tablet. It’s important that you have snacks and medication on hand at all times.

You shouldn’t resume driving until your blood sugar has reached and held an acceptable range for 30 to 60 minutes. This is about how long it takes for your cognitive capabilities to return to normal.

You should plan to stop at regular intervals to test your blood sugar. This is especially true if you’re driving a long distance or over a long period.

If you experience any symptoms of low blood sugar at any time, you should stop at a rest stop and check your levels immediately.

Each person’s medical needs vary regardless of whether they have diabetes, and no two cases of diabetes are the same. Your doctor will assess your individual symptoms and make a recommendation that’s appropriate for you.

If your doctor says it’s OK for you to drive, you should be able to retain or apply for your license successfully. If your doctor finds that you may be unable to drive safely, you can discuss your other options for transportation with them. Depending on your situation, this may include having a friend or family member drive you around or using public transportation.

Keep reading: Diabetes and diet: What to eat and what to avoid »