The Physiological Mechanism of Suppressing and Improving the 'Excessive Excitement of the Sympathetic Nervous System', the Root Cause of Psychogenic ED, Through Stress Relief and Parasympathetic Approach via Chewing (Masticatory Behavior)

Among erectile dysfunction (ED), a representative male sexual dysfunction, the biggest factor causing “Psychogenic Erectile Dysfunction (pED)”, which is not accompanied by organic diseases of blood vessels or nerves, is reported from comparative studies of autonomic nervous system data to be “chronic overactivity of the sympathetic nervous system and runaway HPA axis” caused by psychological stress. And as an effective physical intervention to apply the brakes from the center to this runaway sympathetic nervous system and restore the tone of the parasympathetic nervous system essential for the initiation of an erection, the anti-stress mechanism by “chewing” is once again attracting attention.

This content explains based on research investigating the relationship between autonomic nervous activity and stress hormones in psychogenic ED patients.

Hypothalamic-pituitary-adrenal axis activity and its relationship to the autonomic nervous system in patients with psychogenic erectile dysfunction | Frontiers https://doi.org/10.3389/fendo.2023.1103621

”Autonomic Imbalance” and HPA Axis Overactivity Peculiar to Psychogenic ED Patients

An extremely important prerequisite in the physiological process of initiation and maintenance of an erection (Tumescence) is that “sexual stimulation is transmitted from the cerebrum, the parasympathetic nervous system becomes dominant, nitric oxide (NO) is released, and the vascular smooth muscles of the corpus cavernosum undergo sufficient relaxation.” Conversely, when a person is in a state of tension or under environmental stress (when the sympathetic nervous system is excessively excited), it acts in the direction of constricting blood vessels, so an erection is physically inhibited and attenuated (Detumescence).

In the aforementioned study comparing physiological data between a group of stress-induced psychogenic ED (pED) patients in modern society and a healthy control group, the following prominent abnormalities were confirmed in the internal environment of pED patients.

• Sympathetic Hypertonia (Increase in LF/HF Ratio): In the frequency analysis of heart rate variability (HRV), the patient group was clearly in a state where the “LF/HF ratio,” which indicates the activity level of the sympathetic nervous system, was elevated.
• Suppression of the Parasympathetic Nervous System: At the same time, the HF component indicating a relaxed state and indicators showing the function of the parasympathetic nervous system between heartbeats (such as pNN50) were significantly reduced.
• Enhancement of Stress Hormone Secretion: Not only was the psychological stress evaluation score (PSS-10) significantly higher, but it was also found that the “Hypothalamic-Pituitary-Adrenal (HPA) axis,” the brain and endocrine network governing stress, was excessively activated, and they continued to be exposed to high concentrations of stress hormones.

As shown by experimental results (e.g., PMC4004643) where the increase in erection is inhibited immediately following the sudden excitement of the sympathetic nervous system due to acute nicotine ingestion, the disturbance of the autonomic balance functions not as a “result” of ED but as a direct “mediator.”

Utilizing the Central Stress Buffer Function through “Chewing”

Against these psychogenic factors, the repetition of “chewing exercise” functions as a bio-hack to forcibly adjust the tone of the autonomic nerve center in the brain without relying on drug administration.

The act of continuously chewing food or gum at a constant tempo and intensity (rhythmic chewing) continues to send input signals from sensory receptors through the trigeminal nerve to the reticular formation of the brainstem and elsewhere. From numerous past neuroscientific findings, it has been shown that this chewing input causes specific “anti-stress (anxiolytic) effects” as follows.

• Through neural projections reaching the hypothalamus, it applies inhibitory feedback (brakes) to the HPA axis, which has fallen into an overactive state.
• It physically reduces the excessive secretion of blood cortisol, etc., due to continuous stress.
• It sedates the abnormal excitement of the sympathetic nervous system and relatively restores the activity of the parasympathetic nervous system.

In other words, it suggests the possibility that the “excessive tension and stress” underlying psychogenic ED can be directly offset by the physical rhythmic movement of the jaw, which is chewing.

The “Strongest Non-Pharmacological Approach” That Simultaneously Reduces Organic Risks

Furthermore, even when looking at the cause of ED onset from the metabolic and vascular side (organic factors), chewing demonstrates a powerful preventive effect. The increased secretion of incretins (GLP-1) caused by chewing well improves insulin resistance, fundamentally reducing the risk of developing obesity, hypertension, and arteriosclerosis as a result. All of these are major risk factors that destroy the function of fine microvessels around the penis and invite organic ED (e.g., warnings by Annals of Internal Medicine).

Intervention in chewing function can solve both the “neural approach in the center” of relieving psychological stress and turning on the parasympathetic nervous system, and the “vascular approach in the periphery” of optimizing sugar metabolism and maintaining the softness of the vascular endothelium all at once. Therefore, it is considered to function as an extremely safe and rational daily preventive measure for the maintenance and recovery of sexual function.