Two Drinks Can Impair Seniors’ Avoidance of Obstacles

Two drinks a day fall within the “healthy allowance” for men, and aren’t really excessive for women.  And they aren’t enough to exceed the blood alcohol limit for drunk driving laws (0.08% in the USA).  Indeed, in my youth there was expression to describe someone who’d drunk too much – they’d had “one-over-the-eight”, implying that up to 6 drinks wasn’t too many.  So the findings from a small Dutch study reported online in BMC Research Notes are somewhat surprising.   

Thirteen healthy 60-year-olds (9 men, 4 women) volunteered; none of them were habitual drinkers.  They were asked to walk on a treadmill with a wooden batten held by a magnet in front of them; releasing the magnet allowed the operator to drop the batten onto the treadmill.  Different timing was used, to drop the obstacle at different stages in the participant’s step cycle.  The subject was to step over the obstacle with their right foot.  Reaction times in the femoral muscle were recorded electronically.  Avoidance failure rates were also recorded.

Three series of 30 obstacle avoidance trials were performed, each 30 minutes after a drink. The subjects were told the drinks contained alcohol, and they should finish them within 10 minutes.  The first drink was a placebo (water mixed with orange juice with a drop of vodka floated on top to give the scent of alcohol.  The following two drinks each contained 40% vodka mixed with orange juice.

After the second drink (the first vodka) 12 of the 13 participants had slower reaction times.  After the 3^rd drink (second vodka), all the participants’ response times were significantly prolonged compared with the placebo times, and they were correlated with the individual blood alcohol levels, which ranged from 0.03% to 0.06%.  The avoidance failure rates increased significantly from 4.5% (after placebo) to 8.8% after two alcoholic drinks.

This small study shows that after 2 drinks – enough to raise the blood alcohol level, but not to legal driving limits – obstacle avoidance reactions are inadequate and too small.  Seniors should take note of these findings.  They might not be so good at “holding their liquor” as they were in their youth . . .