Mental Fatigue Might Be Not So Bad for Exercise Performance After All: A Systematic Review and Bias-Sensitive Meta-Analysis

Daniel Sanabria is awarded with a grant PSI2016-75956-P from Ministerio de Economía, Industria y Competitividad, Miguel A. Vadillo is awarded with grants 2016-T1/SOC-1395, from Comunidad de Madrid (Programa de Atracción de Talento Investigador, 2016) and PSI2017-85159-P from Ministerio de Ciencia, Innovación y Universidades. José C. Perales’ research is supported by a grant PSI2017-85488-P from the Ministerio de Economía y Competitividad, co-funded by the Fondo Europeo de Desarrollo Regional, FEDER, European Union. The funders were not involved directly in the preparation of this manuscript.All authors have made substantial contributions to various elements of the study. Conceptualization: Darías Holgado, Daniel Sanabria, José C. Perales, and Miguel A. Vadillo Data curation: Darías Holgado Formal analysis: Darías Holgado and Miguel A. Vadillo Methodology: Darías Holgado and Miguel A. Vadillo Project administration: Darías Holgado, Daniel Sanabria, José C. Perales, and Miguel A. Vadillo Supervision: Daniel Sanabria, José C. Perales and Miguel A. Vadillo Writing – original draft: Darías Holgado Writing – review & editing: Daniel Sanabria, José C. Perales, Miguel Á. VadilloThere is an ongoing debate in the scientific community regarding whether a state of mental fatigue may have a negative effect upon a range of objective and subjective measures of human performance. This issue has attracted attention from several fields, including sport and exercise sciences. In fact, a considerable body of literature in the sport science field has suggested that performing a long and demanding cognitive task might lead to a state of mental fatigue, impairing subsequent exercise performance, although research in this field has shown contradictory results. Here, we performed a meta-analysis to investigate these inconsistent findings. The analysis yielded small-to-medium effects of mental fatigue on exercise performance, d z = 0.50, and RPE, d z = 0.21. However, a three-parameter selection model also revealed evidence of publication or reporting biases, suggesting that the bias-corrected estimates might be substantially lower (0.08 and 0.10, respectively) and non-significant. In sum, current evidence does not provide conclusive support for the claim that mental fatigue has a negative influence on exercise performance.Comunidad de Madrid PSI2017-85159-PMinisterio de Ciencia, Innovación y Universidades PSI2017-85488-PEuropean CommissionMinisterio de Economía y CompetitividadEuropean Regional Development FundMinisterio de Economía, Industria y Competitividad, Gobierno de España MINECO 2016-T1/SOC-139