Diabetics With Low Blood Sugar at Risk for Driving Accidents
Feb. 25, 2000 (Atlanta) -- Diabetics with even mildly low blood sugar -- hypoglycemia -- can find their driving performance seriously impaired, leading to more missed stop signs, inappropriate braking, fast driving, and sudden-stop crashes, according to a small study in Diabetes Care.
What's more, when drivers don't take immediate corrective action -- drinking a soda or pulling off the road -- brain activity changes may prevent their ever taking any corrective action, leading to a stuporous state that can cause serious accidents, the study shows.
"There were individual differences, of course, but as a group [diabetic patients in the study] drove worse when they were mildly hypoglycemic than when [blood sugars were normal]. But the [impaired judgment it caused] was most interesting and quite distressing," lead author Daniel J. Cox, PhD, of the Behavioral Medicine Center at University of Virginia Health System in Charlottesville, tells WebMD.
Chronic low blood sugar causes brain function and judgment to become temporarily impaired. "We had patients telling us, 'I knew I was going hypoglycemic, I knew I needed to treat myself. I had a sandwich right next to me but I couldn't make myself take it, I couldn't make myself eat it,'" Cox says. "That's why it's so critical to treat yourself right away. Don't wait till you get to the office to treat yourself. Do it immediately."
Using a sophisticated driving simulator (developed with help from NASA flight simulator engineers), Cox's team was able to document that driving impairments occur at relatively mild degrees of hypoglycemia (blood glucose levels in the 60s).
The study involved 37 adults with type 1 diabetes and an average age 35 -- all of whom had been taking insulin for at least two years. During the 30-minute driving test, each was given insulin intravenously to progressively lower blood glucose levels.
During the first hour, each volunteer drove the simulator for 30 minutes while blood sugar levels were normal; during the second 30-minute test, blood sugar levels were decreased to hypoglycemic levels. Patients were unaware that their blood glucose levels were being altered. Driving performance, brain activity, and corrective behaviors were continually monitored -- every five minutes -- as were blood glucose levels, perception of symptoms, and impaired judgment.