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Simultaneous Physical and Mental Effort Alters Visual Function

Vera, Jesús PhD1; Jiménez, Raimundo PhD1; García, José Antonio PhD1; Cárdenas, David PhD2,3

doi: 10.1097/OPX.0000000000001105
Original Investigations

PURPOSE: Perceptual processing is sensitive to physiological changes. Thus, the homeostatic disturbances during and after exercise may alter the visual function. Here, we investigated the effect of simultaneous physical effort and two levels of cognitive demand on skills related to the visuoperceptual and motor processing.

METHODS: Eighteen male regular exercisers performed 60 minutes of simultaneous physical exercise (cycling at 60 ± 5% of reserve heart rate) and cognitive effort (mental workload). The same protocol was performed with a mental workload and an oddball condition of this task on different days in a counterbalanced manner. We assessed the near point of convergence, near stereoacuity, accommodative facility (Hart Charts), and eye-hand coordination before and after the two dual-tasking sessions. Also, we calculated cognitive-performance scores and subjective measures of mental load.

RESULTS: We found that the near point of convergence (break and recovery) is significantly (P ≤ .05) reduced after physical and mental effort independently of the mental level administered. Only the condition of mental workload with simultaneous constant-intensity cycling promoted a significant impairment in the near stereoacuity and the eye-hand coordination (P = .006 and P = .018, respectively); however, these two parameters did not significantly change under the oddball condition. The accommodative facility showed an improvement in the oddball and mental workload conditions (P < .001 and P = .006, respectively). Confirming a successful experimental manipulation, participants experienced higher mental demand and arousal and achieved lower scores on cognitive performance during the mental workload task (both P < .001).

CONCLUSIONS: The visual function is affected by simultaneous physical and mental effort, the manipulation of mental-task complexity being an important modulator of this effect. Both dual tasks, physical with or without mental workload demands, may enhance or impair visual and motor processing depending on the visual parameter tested, and those changes could be related to the activation state of the nervous system.

1Department of Optics, Faculty of Science, University of Granada, Granada, Spain

2Department of Physical Education and Sport, Faculty of Sport Science, University of Granada, Granada, Spain

3Sport and Health University Mixed Institute, University of Granada, Granada, Spain

Corresponding Author: Jesús Vera Department of Optics University of Granada Campus de la Fuentenueva 218001 Granada Spain e-mail:

Submitted: July 20, 2016

Accepted: May 25, 2017

Published Online: July 14, 2017

Funding/Support: This work was supported in part by the Spanish Ministry of Economy and Competitiveness under grants DEP2013-48211-R and FIS2013-42204-R and CEMIX (Centro Mixto UGR-MADOC, Army of Spain) under grant PIN 11.

Conflict of Interest Disclosure: None of the authors have reported a conflict of interest.

Author Contributions and Acknowledgments: Conceptualization:JV, RJ, DC; Data curation: JV, RJ; Formal analysis: JV, RJ; Investigation: JV, RJ; Funding acquisition: DC; Methodology: JV, RJ, DC; Project administration: JAG, DC; Resources: RJ, JAG, DC; Supervision: RJ, DC; Validation: RJ, JAG, DC; Visualization: JV, RJ, DC; Writing – original draft: JV, RJ; Writing – review & editing: RJ, JAG, DC.

The authors thank David Nesbitt for translating the text into English. They also thank José Cesar Perales for his valuable comments and Juan Carlos de la Cruz for his assistance during maximal incremental tests. The authors gratefully acknowledge the participants who gave of their time to collaborate in the present study.

© 2017 American Academy of Optometry