By Carol Church, Writer, Family Album

Reviewed by Linda Bobroff, PhD, Department of Family, Youth, and Community Sciences, University of Florida

When we enjoy a dinner out with friends, plenty of us order a glass of wine, a beer, or something stronger along with our meal. It’s a social ritual, and for many, a delicious option. However, there’s one thing we always have to keep in mind when drinking alcohol away from home: in most cases, someone needs to drive home. And while it takes several drinks for most people to get up to or over the legal blood alcohol limit of .08, what many don’t realize is that driving capacity may become impaired long before we reach this level.

Now new research at the University of Florida suggests that drivers over the age of 55 may be especially prone to poor driving performance after drinking, even when their blood alcohol remains below the legal limit. In an experiment, 72 people first used a driving simulator to “drive” an easy course while completely sober. The machine tracked their skill and any errors made. Next, all the “drivers” were given a beverage to drink. Some were given enough alcohol to make them slightly impaired (though under the legal limit), some were given just a small amount of alcohol, and some were given soda “spritzed” with a trace of alcohol to make it smell alcoholic. Half the drivers were between the ages of 25 and 35, while the other half were between 55 and 70.

The drivers then “drove” the same course again. Results showed that the older drivers’ performance was significantly affected at blood alcohol levels of .065. (For a woman weighing 120 pounds, this is about two beers over the course of an hour or so; for a man weighing 160 pounds, it’s about three.) Under these conditions, older drivers were more erratic in how they steered and how they controlled their speed. Meanwhile, the younger drivers’ performance was not noticeably impaired by this level of blood alcohol.

The researchers conclude that older drivers may be quite a bit more sensitive to the effects of alcohol, a finding supported by previous research. Based on these results, drivers over 55 may want to be especially cautious about drinking when they plan to drive. As the authors point out, these changes in how we tolerate and handle alcohol may be hard to detect, especially for those who have been drinking socially for years. All the more reason to plan ahead and designate a sober driver.

(Photo credit: sundowner by jenny downing. CC BY 2.0.)

References:

Blood alcohol calculator. (2010). Retrieved from http://bloodalcoholcalculator.org/

Sklar, A. L., Boissoneault, J., Fillmore, M. T., & Nixon, S. J. (2014). Interactions between age and moderate alcohol effects on simulated driving performance. Psychopharmacology, 231, 557-566. http://dx.doi.org/10.1007/s00213-013-3269-4

Wisconsin Department of Transportation. (2014). Blood alcohol content calculator. Retrieved from http://www.dot.wisconsin.gov/safety/motorist/drunkdriving/calculator.htm

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