According to a recent study published by researchers at U of T’s Rotman Research Institute, older adults are more alert and perform better at challenging cognitive tasks in the morning. 

The study, published in the journal Psychology and Aging, suggests that older adults are more likely to use regions of the brain associated with improved ability to resist distraction earlier in the day. When tested in the afternoon, they show a decline in both their behavioural and neural condition.

There are fluctuations in our hormonal levels and our cognitive alertness throughout the day known as a circadian rhythm. This “inner clock” is affected by many different variables, including age. 

“Our research is consistent with previous science reports showing that at a time of day that matches circadian arousal patterns, older adults are able to resist distraction,” Dr. Lynn Hasher, U of T professor and senior author on the paper, said in a Baycrest press release.

Researchers asked groups of younger and older adults­­­—aged 19–30 and 60–82, respectively—to perform tasks including studying and remembering sequences of pictures and combinations of words that appeared on the computer screens. They also included distactions such as flashing irrelevant words or images on the computer screens. At the same time, they scanned the brains of the participants using functional magnetic resonance imaging to detect the regions that were activated. 

The results showed significant differences between the brain scans of older adults and younger adults performing tasks in the afternoon. However, this was not the case when both younger and older adults performed tasks in the morning.

When older adults engaged in tasks in the afternoon, the brain regions involved in suppressing distractions were activated only 5.4 per cent as often as they were for younger people. Conversely, when the older adults performed the same tasks in the morning, they activated the same brain regions a whopping 41.4 per cent as often as their younger counterparts. Those tested in the morning were not as easily distracted as their peers tested in the afternoon and therefore had greater cognitive ability.

John Anderson, PhD candidate and lead author of the study said in the press release, “[The older adults’] improved cognitive performance in the morning correlated with greater activation of the brain’s attentional control regions—the rostral prefrontal and superior parietal cortex—similar to that of younger adults.” 

The study results propose that challenging tasks should be scheduled in the morning for older adults since they are more alert and therefore will be able to perform better mentally. Researchers should factor in the time of day when studying age differences in brain function.

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