Research assessing the effects of age on physical actions and cognitive processes is often conducted in isolation. However, action and cognition often interact in daily functions and deteriorate with age. Therefore, assessing how motor actions affect core cognitive abilities and how age amplifies these effects is pivotal. The present study tested the effects of effortful physical exertion (isometric handgrip) on working memory (WM) and inhibitory control in young and older adults. Using a novel dual-task paradigm, participants engaged in a WM task with 0 or 5-distractors under concurrent physical exertion (5% vs 30% individual maximum voluntary contraction, MVC). Given our previous understanding that high physical exertion impairs inhibitory control, we hypothesized 1) inhibitory control of access to WM will be compromised under high physical exertion and 2) this effect will be amplified by age. Effortful physical exertion, although failed to affect WM accuracy with 0-distractors present for both age groups, reduced WM accuracy for the older, but not young adults, with 5-distractors present. Similarly, older adults experienced greater distractor interference with 5-distractors present under high physical exertion, indexed by slower reaction time (RT), confirmed by hierarchical Bayesian modeling of RT distributions. Our findings that a simple but effortful physical task may result in impaired cognitive control may be empirically important for understanding everyday functions of older adults. Reduced inhibitory control and physical abilities may pose a problem for older adults as the negative interactions between cognitive and motor tasks may impair daily functions and possibly increase the risk of injury.
Multicomponent Fitness Training Improves Walking Economy in Older Adults
