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What causes uncontrollable cramps or shaking?

July 10, 2019

There are many reasons a person may suffer bouts of shaking or cramps, though hydration and rest can often alleviate the affliction. Uncontrollable shaking is not necessarily a sign of serious illness, but it can be.

A person holding their shaky hands together
Image: picture-alliance/dpa/H. Wiedl

Shaking or cramp attacks can be very disturbing. The afflicted person can suddenly lose control of parts or all of his or her body. Sometimes such shaking or cramping can cause the person to fall to the ground and even lose consciousness.

Symptoms can vary. Sometimes they appear together, in other cases they may occur in isolation. Attacks can last for seconds or even minutes before they subside, often when a person begins moving.

Numerous causes

Dehydration, or lack of fluids, is often a possible cause. The human body consists of roughly 70% water, and the brain as much as 90%. Water furnishes our cells with nutrients and oxygen, while at the same time washing away waste through our kidneys.

Read more: Does Parkinson's disease develop in the stomach?

If a person does not drink enough water, sweats profusely, or loses fluids through vomiting or diarrhea, it disrupts the body's fluid balance. If fluids are not quickly replenished, the blood thickens and the entire body goes into a state of alarm, and thus begins to cramp or shake.

The risk of dehydration is especially high among children or elderly people. As the sensation of thirst subsides as we age, older people simply don't realize they lack fluids. Hypoglycemia, or low blood sugar, can also cause cramps.

For instance, an individual that has strained their body, suffers pain, is exhausted, or drinks too much caffeine may suffer violent shaking, a phenomenon known as physiological tremor. When the body is cold, muscles begin to twitch in order to create warmth and keep an individual from going into hypothermia. That is why we shiver as soon as our body temperature sinks below 35 degrees Celsius (95 degrees Fahrenheit).

A possible sign of serious illness

Yet the causes of cramping or shaking can also be illness related. Often such fits are a symptom of epilepsy. But they may also be caused by circulatory disturbances or damage to the brain or the cerebral membrane.

Epileptic fits are "unprovoked," meaning they have no obvious cause, and are recurring. They may, in part, be caused by brain illness, stroke, or tumors — a phenomenon known as symptomatic epilepsy.

Nonepileptic cramp attacks occur when the brain is irritated, for instance by medicine, infection, or fever.

Shaking while at rest, or when moving

When such tremors occur is also key, that is, whether they happen if a person is still or in motion. If shaking disrupts a person's motor skills, causing them to sway or walk in an unusually broad-legged fashion, it could be an indication of brain damage.

However, sometimes shaking occurs when a person is at rest, making it impossible to tighten certain muscles in order to keep them still. The most common form of such resting tremors is Parkinson's disease. 

More common still, are so-called essential tremors. These are likely hereditary, neurological motor disorders that appear between the ages of 20 and 60 and become worse over time. The symptoms of essential tremors are most readily seen when an individual is forced to maintain a stressful body position for a long period of time, or when one wants to make a specific movement. Symptoms often affect the hands or arms, and sometimes the head and even the voice.

Comprehensive rather than remote diagnosis

Relaxation exercises can often help a person avoid cramps, as stress and tension can make shaking worse. Alcohol and caffeine should also be avoided. However, if a person suffers from illness-related tremors it can be a sign of a more serious disease.

Read more: Does nicotine actually help protect against Parkinson's disease?

Ultimately, only comprehensive diagnoses, such as magnetic resonance imaging (MRI), computer tomography (CT), or electroencephalography (EEG) can provide clarity. Remote diagnoses seldom provide answers.