No Effects of Mental Fatigue and Cerebral Stimulation on Physical Performance of Master Swimmers, a study published on the Frontiers in psychology, explains in his analysis: "Mental fatigue refers to a psychobiological state caused by prolonged and/or intense periods of cognitive exertion and is characterized by changes in behavioral, cognitive, and physiological responses.
The mechanisms linking mental fatigue to performance are not yet fully understood. Physiological measures associated with aerobic performance, such as the heart rate, blood lactate accumulation, and oxygen consumption, tend not to change due to mental fatigue.
Mental fatigue is a psychobiological state caused by extended periods of cognitive effort, and evidence suggests that mentally fatigued athletes present impaired physical performance. Different ergogenic aids have been proposed to counteract the deleterious effects of mental fatigue, but whether brain stimulation can counteract mental fatigue is still unknown.
This scenario is even more obscure considering the effects of these interventions (mental fatigue induction and brain stimulation) in a very experienced population consisting of master athletes. Ten master swimmers (30 ± 6 years old and 14 ± 8 years of experience) participated in the study."
Mental fatigue on physical performance of Swimmers
The study then added: "They underwent four experimental conditions before an 800-m freestyle test: mental fatigue with brain stimulation; mental fatigue without brain stimulation; absence of mental fatigue with brain stimulation; and absence of mental fatigue and no brain stimulation.
Mental fatigue was induced by a cognitively demanding Stroop Color Test, whereas stimulation was applied on the temporal cortex. After that, the athletes swan 800 m as fast as possible and provided their ratings of perceived exertion (RPE) every 200 m.
Mental fatigue was effectively induced, as evidenced by a greater fatigue perception and more errors in the last blocks of the cognitive task. Mental fatigue induction did not influence performance (time to complete the swimming trial) and RPE.
Similarly, brain stimulation failed to change these two parameters, regardless of mental fatigue induction. The prolonged physical performance of experienced master athletes is not influenced, under the present conditions, by mental fatigue induction, cerebral stimulation, and their association. "