Nighttime leg cramps (also called nocturnal leg cramps or sleep-related leg cramps) are a common condition that causes pain and can disrupt sleep. Symptoms result from involuntary muscle contractions, which are sudden in onset, usually affecting the calf or foot.
Immediate treatment to stop nighttime leg cramps includes:
- Forceful stretching of the affected muscle
- This usually provides rapid relief of the cramp
- Passive stretching by getting out of bed and standing with the foot flat on the floor, then pressing down firmly may provide relief in some cases
Other measures that may help stop nighttime leg cramps include:
- Walking or jiggling the leg followed by elevating the leg
- A hot shower with the stream directed at the cramped area of the body, usually for five minutes, or a warm bath
- Ice massage
For patients who have known fluid and electrolyte balance abnormalities, those should be corrected.
Nocturnal leg cramps are not the same as other nighttime disorders of leg discomfort or movement including restless legs syndrome (RLS) and periodic limb movements of sleep (PLMS).
What Are Symptoms of Nighttime Leg Cramps?
Symptoms of nighttime leg cramps (nocturnal leg cramps or sleep-related leg cramps) typically occur while a person is in bed, but patients may be awake or asleep. Symptoms may include:
- Sudden muscle tightness, most commonly in the calf, foot, or thigh
- Cramps typically last from seconds to many minutes
- Cramps can often be relieved by forceful stretching of the affected muscles
- Calf cramping may be associated with extreme flexing of the foot and toes
- Pain
- Sleep disturbance
- Soreness may last for several hours after the cramp goes away, and discomfort can last up to 48 to 72 hours
- Soreness may last longer if the cramps occur in the thigh versus calf and foot
- Daytime fatigue
What Causes Nighttime Leg Cramps?
There is often no known cause for nighttime leg cramps (nocturnal leg cramps or sleep-related leg cramps) but in some cases, nighttime leg cramps may be secondary to other medical conditions.
Secondary causes for nighttime leg cramps may include:
- Leg positioning
- Prolonged sitting
- Inappropriate leg position during sedentary activity
- Living or working on concrete flooring
- Structural disorders
- Flat feet
- Genu recurvatum
- Hypermobility syndrome
- Neurologic disorders
- Parkinson's disease
- Myopathies
- Neuropathies
- Radiculopathies
- Motor neuron diseases
- Metabolic disorders
- Including fluid volume depletion due to diuretics, excessive sweating without sufficient salt replacement, or fluid removal during hemodialysis
- Electrolyte disturbances
- Pregnancy-related, which may be due to low magnesium
- Diabetes
- Low blood sugar (hypoglycemia)
- Alcoholism
- Hypothyroidism
- Metabolic myopathies
- Use of certain medications
- Inhaled long-acting beta agonists (LABA) and other beta agonists
- Potassium-sparing diuretics
- Thiazide-like diuretics
- Beta blockers with intrinsic sympathomimetic activity
- Angiotensin ii receptor antagonists
- Benzodiazepines
- Teriparatide
- Pyrazinamide
- Raloxifene
- Donepezil
- Neostigmine
- Tolcapone
- Clofibrate
- Cisplatin
- Vincristine
- Oral contraceptives
- Intravenous iron sucrose
- Other conditions
- Exercise-associated muscle cramping
- Peripheral vascular disease
- Venous insufficiency
- Anemia
- Raynaud syndrome
- Opioid withdrawal
- Nonalcoholic cirrhosis
- Bariatric surgery
How Are Nighttime Leg Cramps Diagnosed?
Nighttime leg cramps (nocturnal leg cramps or sleep-related leg cramps) are diagnosed with a patient history and physical examination.
Laboratory testing and other studies are usually not required but it may be indicated in people suspected of having an underlying medical disorder that might be associated with nocturnal leg cramps. Testing would depend on the suspected underlying or associated disorder and may include blood tests such as:
- Potassium and sodium in patients receiving diuretics
- Iron and related testing in patients suspected of restless leg disorder (RLS) or periodic limb movement disorder (PLMD)
- Electrolytes in patients on dialysis
- Magnesium in pregnant women
- Calcium concentration
Patients must meet all three of the following diagnostic criteria of the American Academy of Sleep Medicine for nocturnal leg cramps, as detailed in the International Classification of Sleep Disorders:
- A painful sensation in the leg or foot associated with sudden, involuntary muscle hardness or tightness, indicating a strong muscle contraction.
- The painful muscle contractions occur while lying in bed, although they may arise from either wakefulness or sleep.
- The pain is relieved by forceful stretching of the affected muscles, thus releasing the contraction.
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