Muscle cramps: prevention, diagnosis, and when to see a doctor

A cramp can be relieved in a minute, but it is far more useful to understand why it keeps recurring and to prevent it before an important start. In this article our editors have gathered practical approaches to prevention, an algorithm of what to do during a spasm, and a list of examinations worth undergoing if cramps have become frequent or atypical.

What to do at the moment of a cramp

The most effective and best-studied technique is passive stretching of the affected muscle. During a calf cramp you need to pull the foot toward yourself with the knee straight; for a hamstring spasm, straighten the leg and lean forward; for a quadriceps cramp, bend the knee, pulling the heel toward the buttock.

Stretching activates the Golgi tendon organs, which inhibit excessive motor neuron activity. Usually the spasm eases within 30–60 seconds. Stretch smoothly, without jerks, so as not to damage the already tense fibers.

1. Stop the exercise or reduce the pace.
2. Gently stretch the affected muscle and hold the position until the spasm passes.
3. A light massage after the cramp is relieved helps relax the muscle.
4. If the workout is long and you have been sweating heavily, drink a fluid with electrolytes.
5. Return to work at a lower pace or end the session if the cramp recurs.

Popular folk remedies — pickle brine, mustard, hot extracts — have an interesting scientific rationale. Small studies have shown that sour brine shortens the duration of induced cramps even before it has time to be absorbed. The effect is likely related to reflex inhibition through receptors in the oropharynx rather than to salt replenishment. Still, this is not a substitute for stretching.

After a strong cramp the muscle may hurt for several days. If the pain grows, swelling appears, or the urine darkens — this is no longer an ordinary cramp, and a doctor is needed.

Prevention: training and recovery

Since neuromuscular fatigue is considered the leading cause of cramps during exercise, the main prevention is adequate preparation. A muscle adapted to a specific duration and intensity of work tires more slowly and less often 'breaks down' into a spasm.

In practice this means gradually increasing the load, especially before competitions, and training at a pace and in conditions close to those of the event. Athletes who had cramps at previous competitions benefit from analysis: was the starting pace higher than their real capabilities, was there a lack of sleep, did their nutrition change.

Regular stretching of the most frequently affected muscles is widely recommended, although there is little quality evidence of its preventive effect. It is probably useful above all for people with shortened muscles. Strength work for the calves, hamstrings, and feet increases their fatigue resistance.

Recovery should not be underestimated: sleep, adequate energy value of the diet, and carbohydrates to replenish glycogen. During 'cutting,' the risk of cramps rises, so the calorie deficit should be kept moderate, and sharp manipulations of water and salt should be avoided.

Hydration, salt, and supplements

Drinking 'as much as possible' is not the best strategy. The position of the American College of Sports Medicine (ACSM, 2007) advises preventing a loss of more than roughly 2% of body mass through dehydration, but avoiding excessive water intake, which can lead to hyponatremia. The optimal amount of fluid is individual and depends on the intensity of sweating.

For athletes who sweat heavily and see white salt marks on their clothes, during long workouts in the heat it is advisable to add sodium: isotonic drinks, salt tablets, or salty foods. This is especially important during events lasting more than two hours.

Supplements with magnesium and potassium are popular among athletes, but taking potassium without monitoring lab tests is risky: excess potassium is dangerous for the heart, especially in people with kidney damage or those taking certain blood pressure medications. An ordinary diet with vegetables, fruits, legumes, and dairy products usually meets the requirement.

Quinine was once widely prescribed for nocturnal cramps. However, because of the risk of severe reactions — thrombocytopenia, arrhythmias, allergy — the FDA does not recommend it for treating leg cramps, and the American Academy of Neurology advises avoiding routine use. Tonic drinks with quinine contain a much smaller amount of the substance and are not a medicinal remedy.

Diagnosis: which examinations may be needed

The diagnosis of 'exercise-associated cramps' is made clinically: from the description of the situation, the localization, and the connection to training. If the episodes are typical, rare, and pass quickly, special tests are usually not needed.

When cramps are frequent, occur at rest, in several muscle groups, or are combined with weakness, the doctor looks for secondary causes. A basic set of examinations usually covers a complete blood count, electrolytes (sodium, potassium, calcium, magnesium), glucose, creatinine and kidney function markers, TSH, and also creatine kinase.

Creatine kinase should be measured no earlier than a few days after a hard workout: intense exercise itself raises its level, and the result may be misleading. During the examination it is important to honestly inform the doctor about all medications and supplements — diuretics, statins, stimulants, beta agonists.

If a neurological cause is suspected, a neurologist's consultation, electroneuromyography, and in some cases genetic tests for metabolic myopathies are ordered. If cramps are combined with calf pain when walking that disappears at rest, the doctor may check the leg vessels.

When to see a doctor

Some symptoms require immediate medical care. The editors highlight the 'red flags' that should not wait, and that you should not expect to resolve on their own.

• darkening of the urine (the color of tea or cola), severe pain and muscle swelling — possible rhabdomyolysis;
• cramps together with confusion, nausea, headache during a long event — possible hyponatremia;
• cramps with heart rhythm disturbances, dizziness, fainting;
• cramps that appeared after starting diuretics, beta agonists, or other medications;
• cramps with progressive weakness, numbness, or muscle atrophy.

It is worth making a routine appointment with a family doctor or sports physician if cramps occur more than once a week, interfere with sleep, appear during light activity, or are not connected to obvious overload.

During the visit it is useful to have a diary: when the cramp occurred, which muscle, what training preceded it, how much you drank, what you ate, which medications or supplements you took. This significantly speeds up the search for the cause.

If cramps are related to a prescription drug prescribed by a doctor, do not stop it on your own. The doctor may change the dose, replace the drug, or adjust the electrolyte balance.

Editorial conclusions

During a cramp, passive stretching works best. For prevention, the most important things are gradual preparation, a realistic starting pace, sleep, and sensible nutrition; fluid and sodium are needed above all in the heat and during prolonged work.

Magnesium, potassium, and quinine are not universal remedies: the first two make sense with a confirmed deficiency, while quinine, because of its risks, is not recommended for treating cramps.

Frequent, atypical cramps, or those associated with dark urine, require examination, and some require emergency care.

To dig deeper into the topic, read our articles on the causes of cramps and their link to pharmacology, on rhabdomyolysis, and on proper hydration during training.

References

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