Call them tip-of-the-tongue moments: those times we can’t quite call up the name or word that we know we know. These frustrating lapses are thought to be caused by a brief disruption in the brain’s ability to access a word’s sounds. We haven’t forgotten the word, and we know its meaning, but its formulation dances teasingly just beyond our grasp. Though these mental glitches are common throughout life, they become more frequent with age. Whether this is an inevitable part of growing older or somehow lifestyle-dependent is unknown. But because evidence already shows that physically fit older people have reduced risks for a variety of cognitive deficits, researchers recently looked into the relationship between aerobic fitness and word recall.
For the study, whose results appeared last month in Scientific Reports, researchers at the University of Birmingham tested the lungs and tongues, figuratively speaking, of 28 older men and women at the school’s human-performance lab. Volunteers were between 60 and 80 and healthy, with no clinical signs of cognitive problems. Their aerobic capacities were measured by having them ride a specialized stationary bicycle to exhaustion; fitness levels among the subjects varied greatly. This group and a second set of volunteers in their 20s then sat at computers as word definitions flashed on the screens, prompting them to indicate whether they knew and could say the implied word. The vocabulary tended to be obscure — “decanter,” for example — because words rarely used are the hardest to summon quickly.
To no one’s surprise, the young subjects experienced far fewer tip-of-the-tongue failures than the seniors, even though they had smaller vocabularies over all, according to other tests. Within the older group, the inability to identify and say the right words was strongly linked to fitness. The more fit someone was, the less likely he or she was to go through a “what’s that word again?” moment of mental choking.
As an observational investigation, a one-time snapshot of human capabilities, the study cannot prove that greater fitness is what causes older brains to maintain better processing skills; it can only suggest a correlation. Also, exercise habits were not considered; aerobic fitness, which depends to some degree on genetics, was the variable measured. Nor did the study look more broadly into how fitness might interact with language processing as a person ages. Nonetheless, “fitness has widespread effects on the brain,” says Katrien Segaert, a psychologist at the University of Birmingham who led the study. The areas affected include the frontal and temporal cortices, which are involved in language processing.
Segaert and her colleagues plan to deploy brain scans in future studies to examine just how and where fitness and exercise most affect our ability to call up words. But already, she says, this study hints that staying in shape could influence how well we communicate as we age. “Language is such a crucial skill, such a central part of cognition,” she says, and “being fit may help.”