The aging brain and lifestyle: From humans to bumblebees

Sue Hannaford
February 11, 2016

Humans typically show only a modest decline in cognitive function with normal aging.  However, the effect of aging on the brain is a major research focus because the risk of dementia -- a marked, progressive decline in cognitive function -- increases dramatically with age, such that 1 in 8 individuals over 65 and nearly half of all individuals over 85 have a clinically identifiable memory loss.  Large scale studies have shown that several lifestyle factors (i.e., Mediterranean diet, socially integrated network, cognitive leisure activity, and regular physical exercise) are correlated with better cognitive function and a decreased risk of dementia.  Among these factors, physical exercise has the most support as a protective factor, with studies in humans and animals models showing that exercise slows structural and cellular level markers of brain aging.  Recently my lab has begun researching whether relatively short-lived bumblebees also show age-related cognitive decline, and if so, if bumblebee lifestyle factors play a role.  My students and I have compared learning performance, brain structure, and cellular markers of aging in bumblebees with differing levels of physical exercise.  Our results show that the bees that leave the hive to forage on flowers (i.e., have the highest amount of exercise) perform worse in learning tasks and have decreased levels of antioxidants than do in-hive workers.  These results suggest that while regular exercise is good for the brain, too much exercise may accelerate brain aging.