Mental Fatigue and Endurance Performance

New studies are providing growing evidence for how mental training and mindset relate to athletic performance.

Mental fatigue impairs athletic endurance performance via an increase in perception of effort, rather than via physiological mechanisms, suggests a theoretical research review in Sports Medicine (2018; doi:10.1007/s40279-018-0946-9). Researchers from the University of Canberra Research Institute for Sport and Exercise in Canberra, Australia, and elsewhere conducted the research review on underlying mechanisms for mental fatigue during endurance exercise, since physiological factors such as heart rate, lactate accumulation and neuromuscular function are unaffected by mental fatigue.

Kristy Martin, PhD, lead study author and postdoctoral fellow at the University of Canberra, explains their theory that mental exertion, leading to mental fatigue, consumes cerebral fuel stores related to the neurotransmitter adenosine: “Adenosine acts in two ways, by increasing perception of effort, potentially via its inhibitory action in the brain, as well as by reducing motivation to expend energy, via its interaction with dopamine.” Martin notes that if this proves to be accurate, interventions can be created to reduce the impact of mental fatigue on both physical performance and cognition.

In light of this research, Martin recommends choosing from these strategies to reduce mental fatigue:

• ingest caffeine 2 hours before training;
• swill a caffeine or glucose solution in the mouth during training;
• nap briefly prior to training; or
• use motivational strategies like music, direct competition or monetary rewards.

Martin notes that mental fatigue itself may be used as a training stimulus. For example, athletes can practice training when mentally tired to improve their tolerance of a higher perception of effort. Case in point: Other studies show that elite professional cyclists are more tolerant of mental fatigue than recreational cyclists. See PLOS One 2016: doi:10.1371/journal.pone.0159907).