Why do I need to monitor my blood glucose levels?

It is important to be safe when driving, since this affects both yourself and other road users. Those who are on medications that can lower their blood glucose levels need to be mindful of the safe blood glucose targets for driving and the practical steps to take to maintain safe glucose targets. Hypoglycaemia (low blood glucose) can impair concentration and reaction time; these in turn lead to an increased risk of accidents while driving.

Most people with diabetes who maintain stable blood glucose levels can drive safely, say nurses from Specialty Care Services, Division of Nursing at the Singapore General Hospital (SGH), a member of the SingHealth group.

However, it is important for those with diabetes to take certain precautions before they drive.

Am I at risk of hypoglycaemia while driving?

If you are on insulin injections or on oral glucose-lowering tablets like sulphonylureas, your risk of hypoglycaemia can be increased.

This is in particular if you have:

  • Performed physical activities e.g. shopping, exercising
  • Missed a meal
  • Eaten less than you usually do for a meal
  • Other conditions like renal impairment which can increase your risk of hypoglycaemia from medications

Other medications that can cause drowsiness may also decrease your alertness on the road and your ability to pick up low blood glucose symptoms and signs.

When should I check my blood glucose levels?

  1. Before you drive

    Check your blood glucose level before you drive. Aim for a blood glucose level above 5.0 mmol/L before you start driving.

  2. Check every 2 hours

    If you are on a long car journey, take a break.

  3. When you experience symptoms of hypoglycaemia

    Test your blood glucose level when you experience symptoms such as:

    • Shakiness
    • Sweating
    • Fast heartbeat
    • Headaches
    • Dizziness
    • Tingling sensation in your fingers, lips or tongue
    • Feeling hungry or nauseous
    • Feeling nervous or anxious
    • Feeling irritable

    If not treated, your symptoms can become more severe, and can include:

    • Weakness and difficulty walking
    • Blurred vision
    • Confusion and abnormal behaviour
    • Unclear speech
    • Loss of consciousness
    • Seizures

    If you have these symptoms, you or the people around you should call for an ambulance (995) immediately.

What should I do if hypoglycaemia occurs?

  1. Locate a safe place to stop and park your car.
  2. Remove your ignition key and shift to the passenger seat.
  3. Treat low blood glucose (< 4.0 mmol/L) using the 15/15 rule – 15 g of fast-acting carbohydrate like glucose tablets or fruit juices and testing 15 minutes later.
  4. When your blood glucose level has reached above 4.0 mmol/L, take 15 g of carbohydrate before you start driving e.g:
    • 3 pieces of biscuits, or
    • 1 slice of bread
  5. Start driving only when all your hypoglycaemia symptoms are gone and you are able to perform tasks like mental math – this might take up to 30-45 minutes.

For more tips on hypoglycaemia and driving safely, see the next page.

Ref: O17