Effects of Mental Fatigue on Reaction Time in Sportsmen

Aim: Mental fatigue (MF) has been defined as a psychobiological state commonly caused by
prolonged periods of demanding cognitive activity. However, the differences between women and men in
their reaction times (RTs) to visual stimuli due tomental fatigue remain largely unknown. We compare
the differences in RT and heart rate after an acute intervention of mental fatigue between male and female
athletes. Materials andmethods: For this aim, 64 participants (age 31.7  6.2 y) performed a routine of
15 min of the Stroop test (PsyTool), with 600 tasks and five different colors. Their heart rate (HR) was
registered before, during, and one, three, and fiveminutes after the Stroop test. Meanwhile, the RT was
evaluated before and after the Stroop test. A general linear mixed model (GLMM) and a Bonferroni
post hoc test were used to compare the HR between the conditions and an ANOVA two-way analysis
was used to compare the values pre-/post-Stroop test. ( = 0.05). Results: The GLMMfor HR showed
an effect on the time (p < 0.001) and the time  group interaction (p = 0.004). The RT was significantly
increased pre- to post-Stroop test (p < 0.05); however, therewas no difference between the pre- and post-HR
measurements (p = 1.000) and the measurements one (p = 0.559), three (p = 1.000) and five (p = 1.000) min
after the Stroop test. Conclusion: The present findings suggest that the parasympathetic branch of the
autonomous nervous systemwhich functions as a relaxation systemtends to be activated under increasing
mental fatigue, with a decreased performance (RT) similarly in men and women. Therefore, athletes could
useMF induced during training to improve the time delay related tomotor tasks.