What Causes Leg Cramps or Charley Horse?

So what causes leg cramps or charley horse exactly? Before we go into detail here’s a great video which sums up what causes cramp…


Research shows that typically there are two types of leg cramps:

  • Idiopathic
  • Secondary

What Are Idiopathic Leg Cramps?

This is when the cause of the cramp is unknown. There are however theories on what may be causing them:

  • Abnormal Nerve Activity When Sleeping – Which causes leg cramps at night.
  • Excessive Strain Placed On Muscles – For example when exercising, which may cause cramp during or after the exercise.
  • A Sudden Restriction In The Blood Supply To A Muscle

What Are Secondary Leg Cramps?

This is when an underlying condition is the cause of the cramp such as the following:

  • Exercise – One of the most common causes, which can cause cramp during the exercise or when resting afterwards.
  • Old Age – Tendons shorten naturally over time, which explains why episodes of cramp may increase as we age.
  • Pregnancy – The added weight of carrying a baby can place extra strain on the leg muscles.
  • Liver Disease – A liver with reduced function in unable to get rid of toxins properly, which can cause muscles to go into spasm.
  • Neurological Conditions – These are conditions that affect the nervous system, such as peripheral neuropathology, motor neurone disease and Multiple Sclerosis.
  • Infection & Toxins – Bacterial infections and high levels of poisonous substances in the blood (such as mercury) can cause leg cramps.
  • Dehydration – If your water levels drop, then so can your salt levels also, which may also trigger muscle cramps.
  • Mineral Depletion – A diet lacking in potassium, calcium, sodium or magnesium has been linked to leg cramps. Certain diuretic medication can also deplete these minerals further.
  • Cold Temperatures – Especially cold water.
  • Resting/Lying In An Awkward Position – Increases muscle tension.
  • Summer Heat – This has recently been linked with an increased incidence of cramps.

Medication Side Effects

Medicine has also been linked with triggering cramp. The following medication has been linked with triggering muscle cramps:

  • Diuretics
  • Statins
  • Osteoporosis Medication (such as Raloxifene)
  • Angina Medication (such as Nifedipine)
  • Nitric Acid
  • Anti-psychotics
  • Birth Control Pills
  • Steroids

Want to find out more information on what can help prevent cramps? Check our article here.





Hi I'm Josh and welcome to CureMyCramp.com. I set up this site as a resource for information relating to cramp of various types with a focus on up to date information on ways in which cramp can be reduced and prevented.

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