Cramp: what are the causes and where does it occur? Do you have medicine?


What are cramps?

Cramps, or cramps, are involuntary and painful muscle contractions . They can affect anyone, at any age, but they become more common as you get older. The most affected regions are usually the feet and calf, but any voluntary muscle in the body can be affected.

Approximately 95% of people have experienced or will experience a cramp in life. It is a natural event, but extremely uncomfortable.

Theories about the origin

The origin of cramps is not always known. Its main mechanism is believed to be the hyperexcitation of muscle nerves and this can be caused by several things. In addition, the imbalance of electrolytes and minerals in the body can cause difficulties for muscle relaxation. Some of the theories of the causes are as follows:

Metabolic theory

Metabolic theory states that cramps are caused by the excessive presence of lactic acid in the muscle. Lactic acid is produced when there is effort. This would explain the cramps that happen due to physical activity.

Electrolytic theory

When we sweat, we lose, in addition to water, electrolytes, minerals. This can unbalance the body’s fluids, leaving the electrolyte concentration altered and causing cramps.

Theory of dehydration

The loss of water also causes an imbalance in the body fluids, which could be responsible for involuntary muscle contractions. Water loss can happen during physical activities and in very hot climates.

Environmental theory

This theory states that environmental factors can cause cramps, such as sudden changes in temperature, which could cause blood vessels to constrict and reduce circulation to the muscles, causing cramps.


Although we don’t know for sure what the cramping mechanism is, we do know some situations that may result in involuntary muscle contraction as a result. Are they:

Physical activity

Prolonged physical activity can be a cause of cramps, not necessarily during exercise, but also including this situation. It is common for the person to wake up in the morning with cramps that may have been caused by exaggerating exercise during the day.


Dehydration is a major cause of cramps in the elderly, but it can affect anyone.

Electrolyte imbalance (calcium and magnesium)

Electrolytes are chemical components necessary for muscle contraction and relaxation. Although potassium is often related to cramps, it is the lack of calcium and magnesium that causes most cramps due to electrolyte imbalance.


Pregnancy can cause cramps for several reasons, including the lack of magnesium, common during pregnancy, and increased physical exercise as the woman gains weight as the baby grows.

Blood insufficiency

When there is a vascular block, the blood may not reach the muscles properly and sufficiently. The reduction of muscle oxygenation, in addition to the lack of electrolytes in the muscles, are possible causes of cramps.


Liver diseases, when they are not cirrhosis , reduce the amount of cramps in a patient, but when the disease is cirrhosis, caused by repeated scarring of the liver, involuntary contractions can arise more often than in the case of a healthy liver.


The anemia hinders the transport of oxygen to body cells and this includes the voluntary muscles that, due to the reduction of oxygen, may suffer from cramps.

Sedentary lifestyle

Sedentary lifestyle is represented by a habit of little or no physical exercise. This means that a sedentary person is able to exercise less before the muscles consider the effort exaggerated.

The sedentary person is much more likely to exaggerate in exercise than the person who exercises, since the capacity for effort is lower and the cramps may appear because of this.

Inappropriate position for long periods

An improper position for extended periods of time can cause severe and severe cramps. It is recommended to be well positioned and move frequently in order to avoid exaggeration and cramps, among other harms of sedentary lifestyle.


Between 20% and 30% of patients suffer from reduced blood pressure during  the hemodialysis procedure. Between 5% and 20% of patients undergoing the procedure have cramps.

These two symptoms are believed to be related since in most cases, muscle contractions happen along with pressure drop. The relationship, however, is not clear and there is no clinical certainty as to why cramps happen during hemodialysis.


Fractures can be accompanied by cramps. It is possible that this is a defense mechanism of the body, which contracts the muscles around the injury to protect the region from further damage.

Use of diuretic medications

Diuretic medications cause rapid loss of fluids and electrolytes. If they are not replaced, they can cause dehydration, which in turn can lead to cramps.

Neurological diseases

Neurological diseases affect neurons, which can have consequences for the whole body. An example of a neurological disease that can cause cramps is Alzheimer’s, but several others can do the same.


Myopathies are diseases that affect the muscles. Muscular dystrophies are famous for myopathies, but there are several of them and they are all associated with cramps and involuntary muscle contractions.

Medicines that can cause cramps

Some medications can cause cramps between their side effects. For example the following:

  • Diuretics ( Furosemide );
  • Donepezil (Used for Alzheimer’s);
  • Hypertension medications ( Nifedipino );
  • Broncodilatadores (Salbutamol)
  • Cholesterol medications ( Lovastatin ).


NEVER  self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

How do muscles work?

Cramps are nothing more than involuntary muscle contractions. To understand them, it makes sense to understand how muscles work.

Muscles are divided into three groups: striated , smooth  and cardiac .

Cardiac muscles  are unique to the heart. They are strong, resilient and do not stop for our entire lives, moving involuntarily to circulate blood.

On the other hand, smooth muscles  are those that make up our organs and blood vessels. It is the smooth muscles that carry out the movements of the intestine, gallbladder, stomach and all other involuntary movements of our organs, except the heart.

The muscles that are affected by cramps are the striated muscles . They are the voluntary muscles of our body, the ones that move our legs, arms, fingers and even the tongue.

It is possible to have cramps in any of the striated muscles (including the tongue, although this is very difficult, as this is a very resistant muscle to effort), but they are more common in the calf and feet than elsewhere.

Striated muscle

The striated muscle moves thanks to sarcomeres . Each muscle fiber is made up of thousands of them. These are the sarcomeres that contract to create muscle contraction and movement.

Within the sarcomere there are actins  and myosins . They are composed of chemical elements. Actins are connected to the walls of sarcomeres while myosins are positioned between them.

Myosins have a head that is capable of bending. When we want to contract the muscles, through electrical impulses, the brain orders the release of calcium in the actins, which causes them to attract the myosin head to itself.

When this happens, the actins are pulled to the center of the sarcomere and the walls of the sarcomere are closer to each other, contracting it. This happens with several sarcomeres at the same time, which results in muscle contraction.

For the contraction to occur properly, the presence of ATP and magnesium is necessary . ATP is the acronym for Adenosine triphosphate ( Adenosine triphosphate , in Portuguese) and is a chemical compound that cells use as energy. Without ATP, cells cannot perform their actions and the movement that myosin makes would be impossible.

Magnesium is a mineral salt used for the regulation of muscle contraction and relaxation. In the absence of magnesium, the muscle may have difficulty relaxing and controlling the intensity of the effort. Other mineral salts are also used for relaxation, such as potassium, but magnesium is of great importance throughout the process.

Thus, in the absence of magnesium, cramps become more frequent, as muscle contraction can happen, but relaxation is hampered.

Groups of risk

Some groups are at greater risk of developing and cramping. Are they:


Frequent effort is one of the causes of cramps. Athletes always seek to improve their performance and take their body to a new level of effort, so it is common for training to cause cramps. To avoid them, it is recommended to stretch before exercising.


People with diabetes can lose fluid much faster than a person without the condition. This can make the patient more easily dehydrated, which causes cramps.


Approximately 50% of people over 50 report suffering from night cramps and the number increases with age. The frequency with which the condition arises is around 2 to 3 times a week.

As we age, our muscles lose strength and capacity, and more easily lose necessary minerals, such as magnesium, which prevents cramps. In addition, the elderly have a greater tendency to dehydrate, which also leads to cramps.


Due to the lack of magnesium that pregnancy provides women, pregnant women may suffer from more cramps. In addition, the strain on the muscles increases as the pregnant woman carries extra weight as the baby grows.


The symptoms presented by cramps are few, clear and quite uncomfortable. They are as follows:

Involuntary muscle contraction

It is not intentional, but it is very strong. The affected muscle becomes rigid and contracted. Trying to relax it seems impossible, and for a few minutes, you may feel pain.

The muscles that are hit most often are:

  • Calf;
  • Foot;
  • Thigh;
  • Hands;
  • Abdomen.


The pain can be severe and severe in the muscle affected by the involuntary contraction. When the cramp happens during sleep, the person wakes up because of the pain, which only passes after a few minutes, together with the cramp.

How is the diagnosis made?

The diagnosis is purely clinical. This means that the patient’s reporting of symptoms is enough to diagnose cramps, although it is not enough to identify its causes.

That is why the specialty for the treatment of cramps, when necessary, is not exact. The general practitioner  can raise suspicions based on other symptoms and refer the patient to the appropriate specialist.

When cramps are due to overexertion, the sports doctor  may be the right professional. In the case of neurological or nervous problems, the neurologist  can be recommended.

In addition, the orthopedist , the endocrinologist , the nephrologist , the hepatologist , the nutritionist and the physical education professional also have knowledge that may be relevant to your case, depending on the causes.

Is there a cure?

Cramp is not really a disease, but a symptom. Not all of its causes are known, so it is not possible to eliminate all of them, but it is possible to treat some.

The replacement of the necessary mineral salts, hydration and good nutrition make all the difference, in addition to stretching before each physical exercise.

What is the treatment?

Treating cramps is complicated because not all of its causes are known and someone completely healthy can have them. However, if they are very frequent, visiting a doctor is recommended as there may be a known and treatable cause. In that case, it is possible to reduce the number of cramps.

Although there is no treatment that is guaranteed to rid you of cramps, seizures can be relieved. Waiting to pass is a big part of the process, but there are things you can do to speed it up.

Seek to relax

When you are feeling the cramps of a cramp, relaxing may seem counterintuitive or even impossible, but it is ideal for stopping the pain. Cramps are nothing more than muscle contractions, so relaxing the muscle is the goal.

Find a comfortable position for stretching the muscle, but be careful not to force it. If your cramp is in the foot or calf, you can place the sole of the foot on the floor and bend the knee slightly forward, placing the weight on the leg. This position should be more comfortable and should make the contracted muscle relax.

Stay a few minutes in this position for the cramp to pass.

Massage the region

If the cramp is caused by poor circulation, massaging the area can improve blood flow and relieve pain. Massage also helps the muscle to relax.

Hot compress

Compresses can help to relieve cramps. You can use a thermal bag or a cloth soaked with hot water.

The hot compress helps to relax the muscles, in addition to improving blood circulation in the region.


Cramps rarely have serious consequences and fortunately they usually last for a short time, between a few seconds and a few minutes. They rarely need treatment, unless they are extremely frequent and intense.

What serious illnesses cause cramps?

Although cramps are common and often do not mean anything serious, it can be a sign of serious illness. Some of them are:

  • Parkinson’s disease;
  • Diabetes;
  • Demyelinating neuropathy;
  • Cirrhosis;
  • Hepatitis;
  • Muscular dystrophies.

In addition, tetanus can also cause severe involuntary contractions in the patient’s body, in which case the disease is serious and can kill through these contractions, which are capable of preventing breathing. Tetanus cramps, however, are clearly different from normal.

It is likely that you do not have to worry about these diseases just because you have cramps. They can cause involuntary contractions, but many other things can also.

When to go to the doctor because of cramps?

You should go to the doctor for cramps when:

  • An entire limb (foot, calf and thigh, for example) is affected at the same time;
  • The cramp lasts more than 10 minutes;
  • Weakness after cramp;
  • Swelling or redness in the affected area after the cramp;
  • Very frequent cramps in a short time.

It may also be a good idea to visit a doctor when many cramps happen for no apparent reason (exercise, dehydration, poor diet) as there may be a problem with the body’s absorption of magnesium.


There are not many direct complications of cramps. The pain is strong, but it passes along with the crisis. Muscle injuries are the biggest risk due to cramps:

Muscle injuries

Doing improper stretches during a cramp attack can damage your muscles in a harmful way and cause muscle damage. If you suffer from cramps, avoid forcing the muscles to a position where the pain is greatest, as it is in these cases where the injury can happen.

How to prevent cramps?

Cramps can affect anyone at any time and are not always a sign that something is wrong. However, it is possible to avoid them to save yourself discomfort and pain.


Stretching before practicing physical exercises helps to prevent cramps, improving oxygenation and circulation of the muscles, in addition to preparing them for physical exercises.


Food is important because vitamins and minerals can be replenished through it. Potassium, for example, is essential for muscle function. It can be eaten in bananas or potatoes with peel.

In addition, foods rich in other salts like magnesium also help. This list includes bananas , grapes , grains, nuts, sunflower seeds, among others.


Hydrating makes all the difference. Drink plenty of water throughout the day, especially after exercise.

Just as important as replacing the water is replacing the mineral salts that are lost during exercise. For this you can drink isotonic drinks, which are made to replace not only the water, but also the lost electrolytes.

Foods to prevent cramps

Some foods are indicated to prevent cramps. They have magnesium, which is necessary in the muscle relaxation process. This element is found especially in green foods, with a lot of chlorophyll, such as kale , spinach  and watercress . When in doubt, look for dark green foods.

The banana, which is an excellent source of potassium, is not necessary to prevent cramps, but it is important to help with the electrolyte balance and it does not hurt to ingest it.

You can also make an anti-cramp vitamin. This recipe seeks to add calcium, potassium and magnesium to your diet, three essential salts for the balance of muscle chemistry. The ingredients are:

  • 1 kale leaf;
  • 1/2 apple;
  • 1/2 banana;
  • 1/2 celery stalk;
  • 1 tablespoon of sunflower seed;
  • 1 glass of water.

Beat everything in a blender and drink it once a day, in the morning, to avoid cramps.

Common questions

Does drinking lots of water help prevent cramps?

Yes and no.  Although dehydration is one of the causes of cramps, electrolyte balance is essential (and this is part of hydration!).

Drinking just a lot of water can upset this balance by diluting sodium, magnesium and potassium. So, in addition to drinking water, replace minerals and electrolytes.

Does the position before bed cause night cramps?

No , the position is not related to cramps. Overexertion during the day, dehydration and neurological conditions can be causes, but the position will not influence the cramps.

Why does cramp happen during pregnancy?

There are two reasons for this to happen. The first one involves nutrition. When a woman is pregnant, her nutritional needs increase because she has to nurture, in addition to herself, the baby.

If she does not ingest enough electrolytes for both of them, cramps may appear.

Another reason is the extra effort. The pregnant woman gains a lot of weight while the baby grows. She’s carrying a whole little person all the time! This increases the amount of effort required for all activities.

In addition, the abdominal muscles can be pulled due to the weight and growth of the baby, and this can lead to cramps in the belly.

Does the banana prevent cramps?

Although potassium is necessary for muscle relaxation, the lack of it is not the biggest reason for the presence of cramps. Bananas are excellent sources of potassium, but if the goal is to prevent cramps, foods like oranges can be more effective because of the presence of sodium.

Cramps are involuntary contractions of the muscles and can be incredibly painful and uncomfortable, but they are common and affect almost everyone at least once in their lives.

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