Effects of physical effort on temporal processing.

The interaction between temporal processing and physical effort plays a crucial role in our daily activities. The present study therefore assesses the effects of a simple(est) physical effort (i.e., isometric handgrip) on temporal processing with concurrent time reproduction/production and handgrip tasks. Isometric handgrip can induce physical arousal, thereby accelerating time and leading to overestimation when sensory timing is under physical effort, but underestimation when the motor timing is under physical effort (i.e., arousal hypothesis). Alternatively, handgrip may directly impair temporal processing given the potential competition for attention, resulting in underestimated durations when sensory timing is under physical effort and overestimated durations when motor timing is under physical effort (i.e., competition hypothesis). Our data collected in 2023-2024 revealed that high physical effort increased estimated durations in the time reproduction task with concurrent sensory timing and handgrip (Experiments 1-2) but decreased estimated durations in the time production task with concurrent motor timing and handgrip (Experiment 4), supporting the arousal hypothesis. Two additional experiments ruled out some alternative accounts (e.g., response bias). In Experiment 3, the handgrip effect was absent when time was cued, instead of being experienced, under handgrip. In Experiment 5, the handgrip effects of sensory timing and motor timing canceled each other out (i.e., the El Greco effect) when both sensory timing and motor timing were under handgrip. Overall, these findings suggest that physical effort distorts perceived time, with increased arousal likely contributing to the acceleration of temporal processing. (PsycInfo Database Record (c) 2025 APA, all rights reserved).