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What causes leg cramps or Charlie horses ?

Leg cramps are considered to be a health issue of about 90% people. Check out this article to know the factors that are responsible for causing cramps in muscles of legs. Some preventive measures for Charlie horses are given here.


Leg cramps are caused when sudden contractions take place in muscles of legs. Most commonly involved area where cramping is seen is calf muscles of legs. However, cramps can occur in any part of legs. Cramps are also known as Charlie horses. Since most of the times, leg cramps occur during night time, they are also called as nocturnal leg cramps. In different countries, they are called by different names. Cramps are sudden in onset and cause severe pain. This pain may subside after few minutes, but cramping leaves behind discomfort which may last as long as 24 hours.

Causes of leg cramps

There are many causes of leg cramps. Reason behind cramping is sudden contraction of muscles that may take place in any part of leg. There are many reasons and factors which can result in this sudden contraction.
Following are the causes of leg cramps-
  • Inadequate blood supply : If arteries supplying legs get narrowed due to any cause then it definitely affects the blood circulation i.e., arteriosclerosis of the legs result in inadequate blood circulation or blood supply to extremities. This in turn will cause spasm of muscles resulting in cramp-like pain, especially during exercise or during strenuous outdoor activities. Once exercise is ceased, pain seems to disappear.
  • Inadequate oxygen supply : Again due to build of cholesterol in the arteries which supply legs, oxygen supply gets hampered. Muscles require sufficient amount of oxygen to function at its efficient level and inadequate supply of oxygen disrupts its proper functioning.
  • Imbalance of electrolytes :
    Muscles depend up on electrolytes to contract. Sodium, potassium and calcium are among the important ones. Deficiencies of these electrolytes in the body can result in cramping. Electrolyte deficiency can be seen in individuals suffering from kidney failure, diabetes, dehydration etc. Also, excessive sweating and intake of diuretics can cause electrolyte imbalances.
  • Exercise :
    If muscles of legs are exerted to heavy stress or else used for a long period of time then cramps do occur.
    It may occur immediately or after the phase of exertion. This is the reason that sports people frequently suffer form leg cramps.
  • Idiopathic leg cramps :
    Most of the times, leg cramps occur for no reason i.e., underlying cause is not known. This is seen in case of nocturnal leg cramp. Most of the times we sleep with our knees slightly bent. Our foot points downwards. This position shortens muscles of calves. When muscles are shortened, they contract. resulting in cramps which contracts them further. Stretching relieves cramps. Most of the times when we experience nocturnal leg cramps, we stretch our legs to comfort ourselves and relieve cramp. This stretching makes the fact more compelling. Also, abnormal activity of nerve and abrupt restriction of blood supply during stress can be the causes.
  • Vitamin deficiencies :
    Deficiencies of vitamins like thiamine, pyridoxine, pantothenic acid etc directly or indirectly are associated with leg cramps.
  • Position :
    Over stressing of leg muscles for a prolonged period of time by standing or sitting in a particular position for a long time can cause leg cramps. Also, sleeping in an awkward position can bring leg spasms.
  • Dehydration :
    When body gets dehydrated by losing large amount of fluid and electrolytes, leg cramps occur frequently.
  • Pregnancy :
    Pregnant women especially in later months show deficiency in calcium and magnesium. Muscles require minerals for normal functioning and deficiency thereby leads to frequent cramps. Extra weight put on during pregnancy is another cause.
  • Experience to cold :
    Cold weather can cause muscles of legs to undergo spasm. Even when legs come in contact with extreme cold water, muscles contract which leads to leg cramps.
  • Overweight :
    Excess body weight can exert lots of stress especially on muscles of legs. Too much stressing of leg muscles thereby causes them to undergo cramping.
  • Wrong shoes :
    Wearing wrong shoes is another but a less-known reason for cramping. Sometimes it can be a reasonable cause. All of a sudden when one starts wearing heels instead of flats and cramping is frequently experienced then wrong shoes definitely becomes an underlying cause.
  • Not stretching :
    Leg cramps are a result of poor leg muscles. If muscles of legs are kept strong and supple then cramping may never occur. It is very important to properly stretch leg muscles after a warm up and after showering. Cramping can also be a result of sedentary lifestyle.
  • Diseases :
    Leg cramps can be seen in presence of certain underlying conditions or diseases like hormonal imbalances, amyotrophic lateral sclerosis, neuropathy, kidney diseases, kidney failure, motor neuron disease, salt or potassium imbalance, under-active thyroid gland, trauma to the muscles of legs, Addison's disease, diabetes, diarrhea etc.
  • Liver diseases :
    Inadequate functioning of liver which is seen during cirrhosis, liver diseases, partial or complete liver failure can cause build up of toxins in blood. These toxins can cause cramping of leg muscles.
  • Toxins :
    Excessive build up of toxins in blood like lead or mercury which get entered in body accidentally or due to any other deliberate cause can result in muscle spasm.
  • Bacterial infections :
    Infections caused by harmful bacteria especially tetanus is very well associated with causing of muscle spasms in legs and cramping.
  • Nerve compression
    Lumbar stenosis is a condition in which nerves present in spine get compressed. This compression can also cause cramping in legs.

Medicines causing muscle cramps

Following medicines are associated with muscle cramps-
  • Diuretics : These drugs remove excess amount of fluid from the body. They are prescribed to patients suffering from kidney related diseases, high blood pressure, heart failure etc. They along with removal of body fluids at a vigorous rate also deplete sodium, potassium, calcium and magnesium. Loss of body fluids and deficiency of essential minerals both result in causing leg cramps.
  • >Statins- Medicines prescribed to lower blood lipid levels.
  • Salbutamol- Drug prescribed for patients suffering from asthma.
  • Anti psychotics
  • Birth control pills
  • High blood pressure drugs/ACE inhibitors
  • Steroids
  • Drugs for COPD
  • Domperidone to treat stomach troubles.
  • Beta-adrenergic agonists
  • Pseudo ephedrine to treat sinus and other diseases.
  • Raloxifene- Useful in the treatment of bone related problems. Seen to be affecting women in their postmenopausal stage.
  • Stimulant drugs like caffeine, cocaine, nicotine etc.
  • Tolcapone to treat Parkinson's disease.

If leg cramps occur all of a sudden at the onset of certain drugs then it is very likely that the drugs are responsible for causing muscle spasms. Visit concerned doctor so that he can change the prescribed drugs to prevent cramping. Even certain individuals suffer from leg cramps as withdrawal response. Drugs and substances like alcohol, sedatives, anti-anxiety drugs, narcotics etc have sedative action and abrupt withdrawal causes leg cramps.


Leg cramps are usually harmless and thereby does not seek much attention. They cause severe pain, but it lasts only for certain time. However, in certain individuals, cramping occurs very frequently and thus one has to identify the real cause behind cramping. There are many factors behind its occurrence. Common causes can be dehydration, imbalance of electrolytes, intake of certain drugs, wearing wrong footwear, inadequate supply of blood and oxygen to legs etc. More serious causes can be presence of certain underlying diseases like liver disease, kidney disease, neuron disease etc. Whatever may be the cause, proper diagnosis will prevent its occurrence in the future. Read What to do for sudden leg cramps- Treatment and prevention to know about methods which bring relief in leg cramps as well as preventive measures to keep leg cramps at bay.


Author: Swati Sarnobat15 Mar 2019 Member Level: Gold   Points : 1

Several reasons can cause leg cramps such as dehydration, overuse of a muscle, muscle strain, and sometimes due to inadequate blood supply. Some of the medications also cause side effect and hence you experience leg cramps. The other factors include mineral depletion, and nerve compression. The people who are prone to develop this problem are old people, people with prolonged illness, pregnant women and people who have weaker immunity.

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