The feeling of internal tremors is often described as an invisible shaking or buzzing sensation inside the body. This phenomenon is distinct because the shaking is purely subjective; it is felt intensely by the individual but is not visible to an outside observer. The experience can range from a subtle vibration to a strong internal quake, leading many to search for an explanation for this unsettling symptom.
Understanding the Internal Shaking Sensation
Internal tremors are classified as a sensory symptom rather than a motor symptom, which helps differentiate them from visible tremors. Visible, or external, tremors involve a rhythmic, involuntary oscillation of a body part that is physically observable. The internal sensation suggests that motor neurons are firing at a frequency strong enough to create a feeling of vibration, but not powerful enough to physically move the mass of the limb. The perception of this internal vibration is often amplified when external stimuli are minimal, which is why it is frequently noticed when lying down in a quiet environment. In a state of rest, the brain is no longer occupied with processing movement, allowing for a heightened awareness of subtle internal bodily sensations.
Common Non-Systemic and Lifestyle Triggers
A significant number of internal tremors are linked to factors that temporarily overstimulate the nervous system and are not indicative of a chronic disease. One of the most frequent non-systemic causes is anxiety or chronic stress, which activates the body’s “fight or flight” response. This response floods the system with adrenaline and other stress hormones, leading to a state of hyperarousal. Even when a person does not feel emotionally anxious, this chronic stress can cause the physical symptom of internal trembling.
Lifestyle choices and substances also play a major role in triggering these sensations. High consumption of stimulants, particularly caffeine, can increase nervous system activity and make internal shaking more pronounced. Substance withdrawal, such as from alcohol, can also induce enhanced physiologic tremor felt internally, which is often reversible once the withdrawal phase is complete.
A wide variety of common medications can also cause internal tremors as a side effect. Drugs that stimulate the nervous system, such as certain asthma treatments, or those that affect neurotransmitter levels, like some antidepressants, may induce the sensation. Low blood sugar, known as hypoglycemia, is another metabolic trigger that can lead to a feeling of inner trembling.
Systemic and Neurological Causes
While many cases are benign, internal tremors can also be the initial presentation of underlying systemic or neurological conditions that require formal diagnosis. Neurological disorders that cause visible tremors can also manifest as purely internal vibrations, suggesting they stem from the same neurological pathways. Essential Tremor (ET), the most common movement disorder, is frequently associated with internal vibrations.
The internal sensation can also be linked to conditions that affect the central nervous system, such as Multiple Sclerosis (MS) or Parkinson’s Disease (PD). In PD, these symptoms relate to the loss of dopamine-producing cells, which impacts motor control. For individuals with MS, the immune system’s attack on nerve coverings disrupts signal transmission, leading to various sensory symptoms, including internal vibrations.
Systemic issues affecting the body’s balance must also be considered. An overactive thyroid gland (hyperthyroidism) accelerates the body’s metabolism and can induce an enhanced physiologic tremor felt internally. Deficiencies in certain micronutrients, such as B12, iron, and Vitamin D, have been linked to these inner buzzing sensations. Furthermore, inflammation impacting the nervous system, such as that seen following infections like Lyme disease or in Long COVID, is a potential source of internal vibrations.
Clinical Evaluation and Symptom Management
The first step after experiencing persistent internal tremors is to schedule an appointment with a physician for a comprehensive clinical evaluation. The diagnostic process relies heavily on a detailed patient history, including the characteristics of the tremor and a review of all medications and supplements. Understanding whether the sensation is worse at rest, with movement, or with certain tasks provides important clues.
The physician will typically order blood tests to rule out common systemic causes. These tests often include a thyroid screen to check for hyperthyroidism, as well as checks for electrolyte imbalances or hypoglycemia. A neurological examination will also be performed to assess for subtle signs of underlying movement disorders, such as changes in gait, muscle tone, or coordination.
Management strategies depend entirely on the underlying cause identified during the evaluation. If lifestyle factors are the source, reducing triggers like caffeine and managing stress through techniques like mindfulness are recommended. If a neurological or systemic condition is diagnosed, treatment focuses on managing that specific underlying disorder. In cases where the internal tremor is severe and affects daily life, medication may be prescribed to reduce the intensity of the shaking.