Why Professional Athletes Chew Gum During Games: The Neural and Metabolic Mechanisms of 'Improved Reaction Speed' and 'Sustained Concentration' Brought About by Chewing

It is a common sight to see world-top athletes, including Major League Baseball players, chewing gum during games. This is by no means bad manners or a habit simply for relaxation purposes. From the perspective of sports science and neuroscience, the act of “chewing” is a highly logical “brain hack” for athletes to demonstrate their peak performance and sharpen their “0.1-second reactions” under extreme pressure.

This article unravels the mechanism of how improving chewing power raises an athlete’s reflexes and concentration.

Chewing Controls the “Brain’s Arousal Level”

Performance in sports is not achieved simply by being relaxed, nor is it achieved simply by being highly excited. As stated in the “Yerkes-Dodson Law” in psychology, optimal performance is demonstrated when at a “moderate arousal level.”

• Suppression of Hyperarousal from Pressure: In a state of extreme tension (hyperarousal), such as a critical moment in a game, the brain’s field of vision narrows and muscles stiffen due to the runaway sympathetic nervous system. The constant motion of rhythmically chewing gum stimulates the serotonergic nervous system in the brainstem, acting as a buffer to “smoothly” calm this excessive tension.
• “Raising Arousal” When Fatigued: Conversely, towards the end of a game or when fatigue has accumulated, the physical pump action of chewing sends direct stimulation from the face (trigeminal nerve) to the cerebral cortex, functioning as an “igniter (stimulation of the reticular activating system)” to raise the declining arousal level (concentration) again (related to findings in E11, etc.).

In other words, for top athletes, chewing gum is a switch (control of heart rate variability/HRV) to manually tune their mental status at any given time to the “optimal zone (flow state).”

Reaction Time and Activation of the Hippocampus and Motor Cortex

In sports, reflexes such as “reacting to a flying ball” or “reading an opponent’s movement and acting” are the brain’s processing speed itself.

It has been revealed that the chewing motion is not simply moving the mouth, but significantly increases blood flow to extensive areas of the brain (especially the motor cortex, prefrontal cortex, and hippocampus) (related to E01). Research using functional magnetic resonance imaging (fMRI) has confirmed that performing tasks while chewing gum reduces the reaction speed (reaction time) to visual stimuli by a level of milliseconds compared to when not chewing.

This “slight quickness of judgment” and “smoothness in transmitting commands to muscles” are the decisive factors that divide victory and defeat in top-level competitions.

The Metabolic Switch (DIT) and Inner Body Warm-up

Furthermore, chewing directly contributes not only to the cranial nervous system but also to the body’s energy metabolism (metabolic priming).

By chewing food (or gum), the entire body’s sympathetic nervous system is appropriately stimulated, turning on the switch for “Diet-Induced Thermogenesis (DIT)” (E03). This activates brown adipocytes, making it easier for body temperature to rise from the inside. For an athlete before a game, “chewing” is not merely preparation for nutritional intake, but functions powerfully as part of an “internal warm-up” that warms the entire body from the internal organs and brain, putting it on standby for the optimal state for exercise.

“Chewing power” is an invisible athletic talent. The daily habit of firmly clenching the back teeth (maintaining occlusal force) and strategic chewing interventions during games can be said to be the “third performance-boosting strategy” that should be regarded as equally important as physical training.