NEW YORK (Reuters Health) – Older adults who drank a 12-ounce cup of regular coffee before taking a memory test performed better than their peers who drank decaffeinated coffee, according to new study findings. Not only did caffeine drinkers have higher scores on the test, which was given in the morning and afternoon, but they did not show any decline in memory throughout the day.
Test scores declined significantly between morning and afternoon in people who were regular coffee-drinkers but consumed decaffeinated coffee for a day.
The findings support other research showing that in older adults, caffeine can improve memory, which tends to peak in the morning and decline during the late afternoon, according to Dr. Lee Ryan and colleagues of the University of Arizona in Tucson.
"I think the interesting thing about this study is just how easily we could help older adults to increase their cognitive functioning," Dr. Ryan told Reuters Health, adding that anything that boosts energy levels, including a brisk walk or an afternoon nap, will probably help memory.
"Right now, two things we can say for sure: First, a large majority of older adults will be functioning at their peak in the early morning, so if they're planning an important meeting with their stockbroker, best to do it in the morning. Second, if you're a regular coffee drinker, having a mug of coffee in the afternoon just might help you stay sharp," Dr. Ryan said.
According to the report in the January issue of Psychological Science, at least three quarters of adults over the age of 65 consider themselves "morning" people–meaning they believe that they are at their best in the early hours of the day, compared with less than 10% of younger adults.
To examine the effect of time of day on learning and memory, the researchers administered a verbal learning test to 40 healthy adults over 65 years of age who considered themselves "morning" people. The tests were given at 8 AM and at 4 PM in sessions occurring 5 to 11 days apart.
Study volunteers drank either a 12-ounce cup of coffee with 220 milligrams (mg) to 270 mg of caffeine, or the same amount of decaffeinated coffee, which contains no more than 10 mg of caffeine per serving, 30 minutes before taking the test. All volunteers were regular coffee drinkers.
In an interview, Dr. Ryan explained that caffeine stimulates many regions of the brain and that areas that regulate wakefulness, arousal, mood and concentration are especially sensitive to even low doses.
"We suspect that this accounts for the increase in performance. If so, caffeine would have an impact on a wide variety of cognitive functions, not just memory," she said.
The findings may not apply to younger adults, for whom caffeine does not appear to have the same effect on memory unless they are tired or sleep deprived, Ryan said. They also may not apply to people who are not regular coffee drinkers, who might have negative effects of coffee-drinking, such as shakiness, anxiety and decreased concentration