Adults aged 50 and older may become more impaired after one or two alcoholic drinks than they realize, study findings suggest.

In tests on older drinkers and those aged 25 to 35 years, the older group was slower, by about 5 seconds, in completing visual-motor tests, Rebecca Gilbertson told Reuters Health.

A difference akin to "successfully being able to apply the break while driving," noted Gilbertson of the University of Florida in Gainesville.

At the same time, older drinkers perceived themselves as less intoxicated and less impaired than their younger counterparts, Gilbertson and colleagues report in the Journal of Studies on Alcohol and Drugs.

The researchers enlisted 42 men and women who were 57 years old on average, and 26 men and women who were 29 years old on average, to take tests that required them to connect numbered dots and alternating numbers and letters after drinking alcohol or a similar-tasting non-alcoholic drink.

The drinkers consumed alcohol to achieve breath alcohol levels of 40 milligrams per 100 milliliters, which approximated levels achieved by drinking 1 or 2 drinks in a social setting. Then, 25- and 75-minutes later, all the participants completed visual-motor tests and reported how intoxicated and impaired they felt.

Overall, older drinkers performed more poorly than younger drinkers on the visual-motor tests at both time points, despite achieving similar peak breath-alcohol levels, while the non-drinking groups showed no such differences.

In the 25-minute post drinking tests, older adults exhibited greater alcohol-related performance decrements, but reported less perceived impairment than younger adults.

While at the 75-minute post drinking assessment — when breath-alcohol levels were descending — "older drinkers actually reported more perceived impairment," Gilbertson's team notes, whereas "their performance measures were relatively unaffected by their mild intoxication."

"Alcohol impairs all adults regardless of age," Gilbertson noted.