The tremor mechanism

What happens when we tremor? Understanding the tremor mechanism will help you appreciate what to expect during practice and why the experience can vary so much from session to session.

What are neurogenic tremors?

Neurogenic tremors are involuntary muscular vibrations that originate in the central nervous system. Unlike voluntary movement, which we consciously initiate, neurogenic tremors arise spontaneously when the conditions are right.

The tremor mechanism is an innate biological process present in all mammals. It’s part of the body’s natural toolkit for managing stress and returning to balance after threat.

Neurogenic tremors are:

• Involuntary — You don’t make the tremors happen through conscious effort. Once initiated, they arise on their own.
• Self-regulating — The tremors naturally adjust in intensity and location. They may move through different parts of the body, change speed, or stop on their own.
• Safe — Unlike pathological tremors (which indicate nervous system dysfunction), neurogenic tremors are a healthy discharge mechanism. They don’t damage the body.
• Variable — The tremor experience differs widely between people and between sessions. There is no single ‘right’ way to tremor.

Characteristics of TRE™ tremors

Research and clinical observation have identified several distinguishing features of TRE™ tremors:

• Postural or isometric activation — Tremors typically emerge in response to muscle fatigue from holding positions, rather than during active movement.
• Augmented at rest — The tremors often intensify when you allow full relaxation in the tremoring position.
• Wide distribution and migratory — Unlike localised tremors, TRE™ tremors can spread throughout the body and move from one area to another.
• Variable amplitude and frequency — Tremors can range from fine, rapid vibrations to larger, slower movements, and can change within a single session.

These characteristics distinguish TRE™ tremors from pathological tremors (like those in Parkinson’s disease) and from shaking caused by muscle fatigue.

Tremors vs shaking

While we often use these terms interchangeably, there is a distinction:

• Shaking typically refers to voluntary or fear-induced whole-body movement.
• Tremoring in the TRE™ context refers specifically to the involuntary neurogenic vibrations that arise from the body’s natural discharge mechanism.

Why animals shake

Observing animals provides insight into the natural function of tremoring. In the wild, animals face regular threats to their survival. What happens after the threat passes is instructive. Animals typically:

1. Orient to ensure safety (looking around, sniffing)
2. Tremor or shake, often visibly and vigorously
3. Rest briefly in a relaxed state
4. Return to normal activity fully recovered

This sequence — threat, response, discharge, restoration — is the complete stress cycle. The tremoring phase discharges the energy mobilised during the threat response, allowing the nervous system to return to baseline.

‘These gyrations and undulations are ways that our nervous system ‘shakes off’ the last rousing experience and ‘grounds’ us in readiness for the next encounter with danger, lust and life. They are mechanisms that help restore our equilibrium after we have been threatened or highly aroused. They bring us back down to earth, so to speak. Indeed, such physiological reactions are at the core of self-regulation and resilience. […] Learning to live through states of high arousal (no matter what their source) allows us to maintain equilibrium and sanity. It enables us to live life to its full range and richness — from agony to ecstasy.’

— Peter Levine, In an Unspoken Voice

Dr Peter Levine, developer of Somatic Experiencing®, documented this pattern extensively. When the discharge phase is blocked, as it often is in humans, the mobilised energy remains stuck, and the stress response never fully completes.

What tremoring feels like

Describing the experience of tremoring is challenging because it varies so much. Nonetheless, here are common elements:

• Onset — After completing the exercises, you lie in the tremoring position. Initially, you may notice your legs feel tired or shaky. Then, often beginning in the thighs or pelvis, vibrations start to arise. For some people this happens immediately; for others it takes several minutes.
• Quality — Tremors can be fine and rapid, or larger and slower. They can be gentle or quite vigorous. They may feel like waves moving through the body.
• Location — While tremors typically begin in the legs and pelvis, they can spread throughout the body into the abdomen, chest, arms, shoulders, jaw, and even face. Different areas may tremor in different sessions.
• Movement — Sometimes the tremors stay in one place; sometimes they move. The legs might shake, then the pelvis might begin to rock, then the belly might undulate. The body has its own intelligence about where it needs to release.

Tremoring may be accompanied by:

• Sensations of warmth, tingling, or movement
• Emotional feelings, from calm to sadness to joy to fear
• Yawning, sighing, or spontaneous deep breaths
• Stomach gurgles (digestive system activating)
• Memories or images arising

No single 'right' experience

There’s wide variation in the tremor experience. Some people tremor vigorously; others experience subtle vibrations. Some have dramatic emotional releases; others simply feel relaxed afterward. All of these are valid. The tremors will be what your body needs them to be.

Why every session is different

One common observation among TRE™ practitioners is that no two sessions are alike. The tremors may be strong one day and subtle the next. They may concentrate in the legs one session and spread to the upper body the next. Emotions may arise sometimes and not others.

This variability reflects the intelligence of the body’s release process. What needs to be discharged changes from day to day based on:

• Recent stress experiences
• Sleep quality
• Physical activity
• Emotional state
• What was released in previous sessions

Trying to replicate a previous session or achieve a particular experience is counterproductive. The practice invites us to meet whatever arises with curiosity rather than expectation.