Leg cramps may be caused by dehydration, low oxygen levels in the muscles, or a buildup of lactic acid from intense exercise. They can also be linked to nutritional deficiencies.
A leg cramp is a sudden, involuntary contraction of a muscle, most often in the calf, but it can also affect the front or back of the thigh.
In most cases, leg cramps are not serious and can be relieved with stretching. However, if they occur frequently, more than once a day, or last longer than 10 minutes, it is important to see a doctor to identify the cause and begin appropriate treatment.
Main causes
Leg cramps can be caused by:
1. Excessive exercise
Exercising too much, such as running or lifting heavy weights with the legs, can lead to muscle fatigue, lactic acid buildup, and a lack of minerals and oxygen in the muscle.
Exercising in hot weather or without proper hydration can also increase the risk of leg cramps, which may happen during the workout or even hours later.
What to do: drink plenty of fluids during exercise, warm up before training, and stretch afterward to help muscles recover, reduce fatigue, and prevent leg cramps.
Also recommended: Muscle Spasms: 6 Common Causes & When They’re Serious tuasaude.com/en/muscle-spasms2. Staying still for too long
Sitting or lying down in the same position for long periods can cause cramps due to lack of movement.
What to do: change positions regularly and avoid staying still for extended periods. If you spend much of the day sitting, take short breaks to stand up and move your legs.
3. Dehydration
Dehydration reduces the amount of water, minerals, and electrolytes in the muscles, which can lead to leg cramps.
It often happens in hot environments, after prolonged sweating, or with the use of diuretic medications.
Other symptoms of dehydration include dry mouth, frequent thirst, low urine output, and fatigue.
What to do: stay hydrated by drinking about 2 liters (around 8 cups) of water per day, especially during hot days or while exercising.
4. Nutritional deficiencies
A lack of certain vitamins, such as B vitamins or vitamin D, or minerals like magnesium, calcium, sodium, or potassium, can cause sudden leg cramps even without a clear trigger.
What to do: consult a doctor or nutritionist to check for deficiencies and get advice on proper supplementation and a balanced, nutrient-rich diet.
5. Pregnancy
Leg cramps are common during pregnancy, especially in the later months, and may also affect the ankles or feet, usually in the morning.
They are related to hormonal changes and reduced blood flow in the legs due to pressure from the growing uterus.
What to do: gently massage or stretch the calf by pulling the heel down and the toes upward, or apply warm compresses to the legs, ankles, or feet. Staying hydrated and eating magnesium-rich foods can help. Calcium, magnesium, or B vitamin supplements should only be used if prescribed by an obstetrician.
6. Medication side effects
Some medications, such as diuretics for high blood pressure or heart conditions, increase water and electrolyte loss, raising the risk of leg cramps.
Statins, which are commonly prescribed to lower cholesterol, are also known to cause cramps as a side effect.
What to do: consult the prescribing doctor to review the medication. If necessary, the dose may be adjusted or the drug changed. Never stop treatment without medical guidance.
7. Liver cirrhosis
Cirrhosis, a chronic liver disease often caused by long-term alcohol use, hepatitis B or C, or fatty liver disease, can lead to painful leg cramps, especially at night.
What to do: treatment must be guided by a hepatologist and may include dietary changes and medications to manage symptoms. In advanced cases, a liver transplant may be required.
8. Hypothyroidism
When left untreated, hypothyroidism can cause muscle issues such as weakness in the thighs and shoulders, along with pain or leg cramps.
What to do: treatment usually involves thyroid hormone replacement with levothyroxine, prescribed by an endocrinologist.
9. Diabetes
Diabetes can trigger leg cramps due to electrolyte imbalances, low blood sugar, peripheral neuropathy, or poor circulation.
These cramps often affect the lower legs and are more common at night.
What to do: treatment should be guided by an endocrinologist and may involve dietary changes, exercise, and medications such as oral antidiabetics or insulin. Read more about the diabetic diet your doctor may recommend.
10. Venous insufficiency
Venous insufficiency occurs when the valves in the leg veins don’t function properly, making it harder for blood to return to the heart.
Also recommended: Chronic Venous Insufficiency: Symptoms, Causes & Treatment tuasaude.com/en/chronic-venous-insufficiencyThis reduces circulation and oxygen delivery to the muscles, which can lead to leg cramps, especially in the calves.
What to do: raising the legs above heart level can help reduce swelling and discomfort. Regular exercise and maintaining a healthy weight are also important. A cardiologist or vascular specialist may recommend compression stockings or, in some cases, surgery.