The brain plays a part in physical performance, but the specific effects of mental fatigue have yet to be well understood. A new study, led by Dr. Walter Staiano at the Department of Physical Education and Sport, University of Valencia, Valencia, Spain, tested the hypothesis that cognitive load alone and intermixed with standard resistance training would induce mental fatigue, increase the rating of perceived exertion (RPE), alter the perception of weight lifting and training, and impair cycling time-trial performance.
To determine how cognitive tasks affected the feeling of physical exertion in a group of 16 men and women, the researchers evaluated the impact of the tasks on the participants. According to their findings, those who were mentally exhausted felt more exhaustion while engaging in physical activity.
Taking the effects of mental fatigue into account during training may help athletes perform better.
This 2-part study employed a within-participant design. Participants in the tests underwent a 90-minute mental challenge that entailed recognising letter sequences on a screen. They then performed a series of repetitions using weights. Before engaging in the physical challenge, a control group watched impartial videos.
A series of resistance training activities in the second experiment followed a 20-minute cycling time trial. Before and after the workouts, they engaged in cognitive activities while a control group watched a neutral film. Participants conducted an online test to determine their level of exhaustion after the cognitive exercises.
The participants who were mentally exhausted in each trial saw an increase in perceived exertion, or how difficult it felt to complete the task. In the second experiment, the researchers also observed that the psychologically exhausted cyclists pedalled less quickly and covered less distance during the cycling time trial.
Professor Chris Ring in the University of Birmingham’s School of Sport, Exercise and Rehabilitation Sciences said, “Athletes will often be browsing on their smartphones in rests between competing and training. All of that requires mental effort, and our results strongly suggest that athletes and coaches need better to understand the effects of these activities on overall performance.”
The researchers advise coaches to limit athletes’ exposure to mentally taxing activities like smartphone use before, during, and after training sessions and tournaments in light of their findings. In the long run, people should consider engaging in “brain endurance training” to bolster resistance to mental exhaustion.
The research team has already started to test the links between mental fatigue and performance among elite athletes in ‘real world’ exercise scenarios.
- Walter Staiano, Lluis Raimon Salazar Bonet et al. Mental Fatigue: The Cost of Cognitive Loading on Weight Lifting, Resistance Training, and Cycling Performance. International Journal of Sports Physiology and Performance. DOI: 10.1123/ijspp.2022-0356