The Brain as the Ultimate Limiter: Mental Fatigue, Central Governor Theory, and Emerging Predictive Frameworks

For most of the 20th century, exercise physiologists explained fatigue in purely peripheral terms: muscles run out of glycogen, ATP is depleted, hydrogen ions accumulate, oxygen delivery hits a ceiling, and the body is forced to stop.

In the late 1990s, South African physician and scientist Tim Noakes challenged that view with the Central Governor Theory (CGT). He proposed that the brain continuously monitors multiple physiological variables and proactively reduces motor-unit recruitment long before any catastrophic failure can occur. In this model, the sensation of fatigue is not a direct readout of the muscular state but a centrally generated perception designed to protect homeostasis.

While CGT sparked intense debate—praised for explaining phenomena like the terminal sprint and criticized for being difficult to falsify—it shifted the paradigm toward central regulation of effort.

Over the past decade, empirical support for brain-centered models has strengthened considerably. Research led by Professor Bart Roelands and colleagues at Vrije Universiteit Brussel in Belgium, in collaboration with Samuele Marcora (University of Bologna), has focused on mental fatigue, a psycho-biological state induced by prolonged demanding cognitive activity.

Roelands’s team’s landmark 2017 systematic review demonstrated that 90 minutes of a Stroop task reliably impairs subsequent endurance performance by 3–15%, elevates rating of perceived exertion (RPE) from the outset, and leaves cardiorespiratory and metabolic markers largely unchanged. Follow-up studies have shown similar decrements in sport-specific skills (e.g., decision-making and accuracy in soccer and basketball) while maximal anaerobic efforts remain unaffected.

These findings align with CGT’s emphasis on central mediation but have led the field toward Marcora’s psycho-biological model, which frames exercise termination as a motivational decision: when perceived effort outweighs the incentive to continue, the athlete reduces or stops exertion. Mental fatigue raises baseline RPE, shrinking the tolerable “effort reserve.”

As of 2025, even more neurocognitively grounded frameworks are emerging that build on and refine these ideas. A notable recent contribution comes from Jeanne Dekerle and colleagues at the University of Brighton in their Metacognitive Inference of Dyshomeostasis (MID) model. Drawing on “predictive processing theory,” the MID model posits that the brain operates as a hierarchical prediction machine, constantly generating top-down expectations about interoceptive signals (e.g., heart rate, temperature, energy availability) to maintain allostasis, the process by which the body maintains stability by actively adjusting its internal state in anticipation of changing demands.

Exercise-induced perceived fatigue arises not from accumulating physiological sensory signals per se, but from a metacognitive inference: the brain detects growing prediction errors (mismatches between expected and actual bodily states) and loses confidence in its ability to minimize those errors and preserve homeostasis.

This “uncertainty” or diminished precision in allostatic predictions is consciously experienced as fatigue—a feeling of diminishing capacity to cope with stressors.
The MID model integrates elements of CGT (anticipatory regulation to avert dyshomeostasis) and the psycho-biological model (effort-based disengagement) while providing a mechanistic explanation rooted in Bayesian brain principles.

Mental fatigue fits naturally here: prior cognitive load consumes attentional and metacognitive resources, reducing the precision afforded to interoceptive predictions and amplifying perceived dyshomeostasis even before physical exercise begins.

Empirical support for this flexibility comes from interventions that partially counteract mental fatigue—caffeine, carbohydrate mouth rinsing, motivational self-talk, being watched, and monetary incentives—all of which lower RPE or improve performance without altering the initial cognitive stressor.

The field has largely converged on integrative models that retain Noakes’ central-regulation insights while incorporating motivational components and, increasingly, predictive-processing mechanisms. The practical implications are influencing elite sport: teams now minimize pre-competition cognitive load, schedule demanding sessions strategically, and employ countermeasures to preserve metacognitive and perceptual resources.

More than 25 years after the Central Governor Theory, the evidence is unequivocal: the brain sets the ultimate limit on performance through anticipatory, predictive, and metacognitive processes; and mental fatigue, by eroding the confidence in those predictions, is one of its most potent modulators.

For Irish dancers, whose performance depends on rapid decision-making (ever come out of a turn and find the other dancer is face to face with you?), precise movements, and the ability to maintain explosive jumps and rhythm under pressure, the science is clear: your brain’s predictive and metacognitive load is just as important as your physical conditioning.

Minimizing cognitive fatigue in the hours and days before a feis or major can help preserve the “precision” of your brain’s internal predictions, lowering perceived effort and improving technical consistency.

Practical strategies include reducing mentally demanding tasks before key rehearsals, streamlining pre-competition routines, protecting sleep, limiting screen time, practicing short bouts of meditation or other self-soothing/calming techniques, cultivating supportive environments, and using proven countermeasures such as caffeine or positive, instructional self-talk (ie. “I’ve trained and I trust my body,” “Go! You have this!”) when appropriate. By treating cognitive load as part of your training—not an afterthought—you give your brain the bandwidth it needs to execute complex choreography with confidence, sharpness, and resilience.

Lastly, research has proven that what feels like complete muscle failure is actually the brain protecting itself. Electrical stimulation (or supramaximal nerve stimulation) still elicits additional force output beyond maximum voluntary effort—the muscle still has the capacity for more work.

The sensation of “dying” or thinking you must give up is the brain’s uncertainty around what is safe and how long the body will be in an heightened state of depleting valuable resources.

It may also be related to how much effort we are willing to give toward a certain goal. If there is a mismatch between the feelings of overwhelming effort and how much a goal matters in that moment compared to our perception of reserve, we will often give up before it’s truly necessary.

What does this mean for an Irish dancer?

Practice 100%-effort full runs during your training and get in your high-intensity aerobic conditioning! The best way to get through fatigue and sustain output is to prepare your body and your brain for the heavy work.

Studies show that including High-Intensity Interval Training (HIIT) and Sprint Interval Training (SIT) not only build a more resilient, efficient, strong body, but it also trains the brain to tolerate suffering. When you’ve been to the pain cave, it does not seem as dark as when you first enter. You learn to navigate discomfort and better predict how much you actually have to give for a time-regulated effort.

Want to know how to incorporate that into your training program? Give me a shout!