Summary – Driving after 17 hours awake can be as bad as driving at 0.05 BAC
Ever felt too tired to drive? Did you know this was probably comparable to driving over the legal limit.
I was doing a bit more research into sleep and performance when I found this University of New South Wales study on the relationship between fatigue and alcohol. This was the other example I used in my Yeah! Sessions talk below, so this won’t be news if you’ve already seen it.
Anyway, the study highlighted something really interesting that I still haven’t been able to get over – staying up late to drive can be as bad as driving drunk.
The study took a group of transportation workers and recorded their reaction speeds at intervals throughout the day and following night, keeping them awake from about 5:30am in the morning until 8:00am the following day.
The same group were also used to test out their reaction speed after several alcoholic beverages.
The study then compared the decline in reaction speed for the group who drank alcohol to the group who stayed up all night.
Here’s a graph that neatly summed up what happened:
On the X-axis, A1 to A5 indicate the alcohol group, whilst S1-S15 show the sleep deprived group. The Y-axis shows the reaction speed time (the higher the rating, the lower their performance).
At A3 the group was at approximately 0.05 Blood Alcohol Content (BAC), the legal driving limit in Australia. This was matched by the sleep deprived group around S12 or 10:38pm at night (appox 16.91 awake for most).
So whilst you may not have had anything to drink, if you’ve been awake for about 17 hours already, you’re reaction speed is about the same as if you were 0.05 BAC. Of course this varies person to person, and some may not cope as well as others after 17 hours awake. At this stage the only way to judge your performance is based on how you feel.