What MMOL should my sugars be at to drive?
“5 to drive!” This is something that I was told by my NHS endocrinologist that has stuck with me. Before driving I always check that my sugars aren’t below 5.0 mmol with my blood glucose meter. It’s always best to do a manual prick test, and do not rely on a continuous glucose monitor like a Dexcom G6 or Freestyle Libre.
But why is it best to use a blood glucose meter to test before driving?
Continuous glucose monitors like Dexcom G6 and Freestyle Libre measure blood sugar through the interstitial fluid, whilst a blood glucose meter measures it directly from your blood. This means that your blood glucose meter is slightly more accurate and is not as affected by site compression as much as your CGM readings will be. Also, we’ve all seen our Dexcom or Freestyle Libre be completely off and have to do a manual blood glucose test anyway!
Your blood glucose meter could save your life
The risk of hypoglycemia is the main danger to safe driving. If your Dexcom G6 or Freestyle Libre gives you the wrong reading, and you don’t know, you could start to experience hypoglycemia symptoms whilst at the wheel. That is serious. Many of the accidents that have happened due to hypoglycemia have occurred because drivers have ignored warning symptoms of hypoglycemia and have carried on driving, thinking they’ll be okay.
Unfortunately, almost 100% of drivers that have suffered an accident owing to the sudden unset of hypoglycemia symptoms did not plan on it, or were not expecting it, and likely thought they would be okay. Obviously, you wouldn’t drive if you thought you wouldn’t be okay. But we all know hypoglycemia can hit us suddenly & fast, so we should be prepared and do our due diligence with a blood glucose test.
What the UK government say about driving & hypoglycemia
The below points are taken from the gov.uk website and DVLA guide.
- Always carry your glucose meter and test strips with you even if you have a CGM.
- You should check your glucose levels less than 2 hours before driving and every 2 hours after the journey as started.
- If glucose is 5.0mmol or less, eat a snack. If it is less than 4.0mmol or you feel hypoglycemic do not drive.
What if I have a hypo WHILST driving?
It is critical to carry an emergency supply of a fast-acting glucose carbohydrate such as glucose tablets in the car with you. If hypoglycemia occurs whilst driving then you should stop the vehicle safely as soon as possible. The DVLA says that if this happens you should switch the engine off, remove the keys from the ignition and move out of the driver’s seat. Even if you are in a rush to get somewhere you must wait 45 minutes after the blood sugars have returned to 5.0mmol. This is because it takes up to 45 minutes for the brain to fully recover from a hypo. After all, that’s why hypoglycemia symptoms can cause us to lose control of our bodies – because our brains are not functioning correctly without glucose.
You must then test glucose levels using a finger prick test reading, and not a CGM.
The DVLA has said that drivers who have any form of diabetes treated with any insulin preparation must inform the DVLA.
More information can be found via the link below and you can read more of our blogs here.
This information is a guide and referenced from the DVLA website. Please see our editorial policy for more information. This information may not be applicable in your country and is intended for a UK audience. Everybody’s diabetes is different and you must consult your doctor or care-giver. This is not medical advice.