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Nighttime cramps are sudden, involuntary, and painful muscle contractions that occur during the night, commonly in the legs, especially the calf muscles or feet. Although common and generally benign, they can significantly affect sleep quality.

Common Causes:
1. Dehydration and Electrolyte Imbalances
Low levels of potassium, magnesium, calcium, or sodium can cause muscle
hyperexcitability.
2. Sedentary Lifestyle or Posture
Sitting for long periods of time or sleeping with your feet in an awkward position (such as on your toes) can trigger them.
3. Excessive Exercise
Overuse of muscles during the day, without proper stretching, can lead to spasms at night.
4. Underlying Conditions

• Diabetes
• Venous or Arterial Insufficiency
• Chronic Kidney Failure
• Hypothyroidism
• Amyotrophic Lateral Sclerosis (ALS) or Peripheral Neuropathies

5. Associated Medications

• Diuretics (furosemide, hydrochlorothiazide)
• Statins
• Beta-agonists
• Corticosteroids
• Lithium

6. Pregnancy
Changes in metabolism and nerve or vascular compression can cause cramps
in the third trimester.

Diagnosis
The diagnosis is usually clinical, based on the patient’s history:

• Frequency, duration, and intensity of cramps
• Physical activities
• Current medications
• Presence of chronic diseases 

If cramps are very frequent, intense, or resistant to treatment, the doctor may
order: Blood tests: electrolytes, kidney function, glucose, TSH Electromyography (EMG): if neuromuscular disorders are suspected Vascular studies (Doppler): if arterial or venous insufficiency is suspected

Treatment and prevention
1. Lifestyle changes

• Gentle stretching before bed, especially of the calves and thighs
• Massages, warm baths, local heat application
• Adequate hydration during the day
• Avoid excessive alcohol and caffeine

2. Medical treatments

• Magnesium supplements (when deficient, or in Pregnant women)
• Change medications if a drug is suspected of contributing to the cramps
• Quinine: Only in severe cases and under close medical supervision, due to its adverse effects

3. Additional Measures
Elevate your legs during rest
Wear appropriate footwear
Avoid tight sheets that keep your feet plantarflexed

Prognosis
In most cases, night cramps are benign and transient. When treatable causes
are identified, symptoms usually improve significantly with simple lifestyle
changes. If they persist or worsen, it is important to seek evaluation.

Raúl Ayala, MD
@MyDoctorOnCall.com