Altered Spatiotemporal Gaze Dynamics During Unexpected Obstacle Negotiation in a Fatigued State.

Humans use their peripheral vision during locomotion to perceive an approaching obstacle in their path, while also focusing central gaze on steps ahead of them. However, certain physiological and psychological factors may change this strategy, such as when a walker is physically fatigued. In this study, 21 healthy participants walked through a dark room while wearing eye tracking glasses before and following intense exercise. Obstacles were placed in random locations along their path and became illuminated when participants approached them. Results indicate that, when fatigued, participants had altered spatial gaze strategies, including more frequent use of central gaze to perceive obstacles and an increased gaze angular displacement. However, there were no changes in temporal gaze strategies following exercise. These findings reveal how physical fatigue alters one's visual perception of their environment during locomotion, and may partially explain why people are at greater risk of trips and falls while fatigued.