Walking-induced fatigue does not increase the risk of falling during physiological aging

Whether fatigue during walking increases the risk of falling is relevant, particularly for older adults. If fatigue leads to gait alterations that increase the risk of falling—and these changes develop faster than individuals can perceive the fatigue that would prompt them to stop walking—the risk of falling could increase dramatically. We evaluated the time course development of gait-induced fatigue while objective markers of fall risk were assessed in young and older adults (age means 24.1 and 68.2 yrs, respectively) who were walking at their usual pace. The role of the prefrontal cortex in this behavior was tested by applying transcranial static magnetic stimulation. Before gait-induced fatigue had developed and again once fatigue was present, the participants walked for certain intervals while performing a dual-task (walking + Stroop test) to assess the interaction between fatigue and dual-tasking on the risk of falling. Fatigue increased linearly with walking time in both groups; however, objective markers of fall risk remained stable and were unaffected by dual-task walking. These findings suggest that gait-induced fatigue does not increase the risk of falling during healthy aging, at least in relatively young older adults.