Is intense exercise bad for your mind? Subjective, behavioral and physiological responses to a cognitive effort to failure

Introduction Most previous research has investigated if a cognitive task reduces the time a person can perform a posterior physical exercise (Holgado et al., 2023). However, no previous research has investigated if performing an intense physical exercise reduces the time a person can complete a cognitive task with an adequate level of performance. The aim of this study was to assess the subjective, behavioral and brain activity responses of performing an intense physical exercise on a posterior cognitive task until failure. Methods In a pre-registered, randomized, within-participant design experiment, 29 physically active participants completed a cognitive task until failure after running at 90% maximal aerobic speed until failure or after walking for 10 min (control condition). During the cognitive task, brain activity was recorded with an electroencephalogram and brain complexity was quantified. Multidimensional subjective experience was assessed with the Temporal Experience Tracing method (TET) (Jachs et al., 2022). Sequential Bayesian analysis for the main hypothesis (intense physical exercise reduces cognitive task performance) until it reached strong evidence in favor of the alternative hypothesis (BF10 > 6), or the null hypothesis (BF10 < 1/6) were conducted. Results The physical exercise induced a reduction in maximal force generating capacity and increased rate of perceived exertion compared to the control condition, evidencing the presence of fatigue. The total duration to complete the cognitive task in both conditions were 4755.8 s (95% CI 3326.8 - 5107.8) and 4308.2 s (95% CI 3902.9 - 5481.2) for the control and experimental conditions, respectively with no difference across sessions (BF10 = 0.329). Subjective experience analysis identified two distinct clusters of task-related feelings, but the time spent in these experiential states did not differ between conditions. However, cognitive task performance was better in the in the phases of low subjective demands. Brain complexity was lower after the physical fatigue condition, indicating a potential shift in physiological states, although neither behavioral performance nor subjective feelings were affected. Discussion/Conclusion In conclusion, our study did not find evidence that short intense physical exercise negatively affected negatively the duration participants could sustain an adequate (or optimal) cognitive effort. However, it offers valuable insights into the dynamic nature of psychological and subjective states during such tasks. References Holgado, D., Mesquida, C., & Román-Caballero, R. (2023). Assessing the evidential value of mental fatigue and exercise research. Sports Medicine, 53, 2293–2307. https://doi.org/10.1007/s40279-023-01926-w Jachs, B., Garcia, M. C., Canales-Johnson, A., & Bekinschtein, T. A. (2022). Drawing the experience dynamics of meditation. bioRxiv. https://doi.org/10.1101/2022.03.04.482237