7 Common Causes of Leg Cramps

Most people experience leg cramps at some point in their life. From the occasional aching sensation to recurring pangs, people cope with leg cramps—also known as “charley horses” or muscle spasms—to varying degrees.

Cramps are involuntary contractions that occur in the muscles for anywhere from a few seconds to minutes on end (or even longer periods in some cases). Mild or severe, the onset of cramping is typically sudden; it may begin during intense exercise or at rest, in bed at night or after hours of being seated at your desk.

However, just because leg cramps can begin suddenly doesn’t mean they come out of nowhere. Muscle spasms in the calves, hamstrings, and thighs result from a number of common causes, many of which can be addressed simply by being aware of what might trigger them. These are some of the main causes of leg cramps:

  1. Dehydration
    • Fluids hydrate the muscles, allowing them to contract and relax with ease. As such, dehydration is a common cause of cramping in the legs. The idea is that when you aren’t sufficiently hydrated, your muscles may stop functioning optimally and start to spasm.
    • Is it possible you aren’t drinking enough water? This could be the reason for the spasms in your leg muscles. According to the Mayo Clinic, individual hydration requirements depend on the person’s diet, gender, age, activity level, climate, and overall health status (including any medications they might take).1
  1. Sleep deprivation
    • Not getting enough sleep is another possible reason for leg cramps. Nocturnal leg cramping in particular, which affects up to 60% of adults, is linked to muscle fatigue and nerve dysfunction—both of which are known to worsen without enough sleep.2 And since sleep is linked to a threshold for pain, the cramping you experience when sleep-deprived may be especially grueling.2
    • Lack of sleep may also cause you to make cramp-inducing decisions you wouldn’t otherwise make. For instance, some people forget to drink enough water when they are coping with fatigue, which can cause cramping via dehydration. Others aren’t as careful when they exercise; they run the risk of overworking the muscles and grappling with exercise-associated muscle cramps.
  1. Mineral depletion & electrolyte imbalance
    • US government health resource MedlinePlus indicates that mineral depletion and electrolyte imbalance can lead to leg cramping.3 Minerals like magnesium and potassium dissolve in water to form electrolytes that ensure muscles are working correctly; electrolyte imbalance via mineral depletion can trigger cramping.
    • So if you aren’t consuming sodium-rich foods or sports drinks after intense exercise, or incorporating enough potassium, calcium, and magnesium into your overall diet (by way of fruits, vegetables, nuts, dairy, whole grains, and other options), then you may risk experiencing leg cramps.
  1. Intense exercise & overexertion
    • Research has linked leg cramps to vigorous exercise, even among the fittest athletes.4 These cramps, however, are divided into two camps. The first is linked to sodium deficit—a form of electrolyte imbalance, as described above—after extensive sweating. The second camp involves overexertion, as a lack of recovery after intense exercise can overwork the muscle fibers and cause spasms.
    • Addressing the first camp should be clear: Add more sodium to your diet, and after intense exercise, replenish your electrolytes. To reduce cramping from overexertion, stretch frequently and modify the intensity of your exercise regimen. In addition, you may want to take a rest day from time to time and avoid ramping up your workouts too drastically in a short period.
  1. Prolonged sitting or standing
    • Our muscles were made to move, recover, and move again. If you spend eight hours seated at your desk each day, or if you run errands that involve standing in line for hours on end, you could be more susceptible to leg cramps than others. A lack of movement is the culprit here, so be conscious of the amount of time you spend sitting or standing.
    • If you stand for a long time with your leg muscles contracted, you may get a leg cramp because you’ve neglected to relax these muscles. To address this, consciously contract and relax your leg muscles and make an effort to sit down and rest each day. Conversely, if you spend your time seated and don’t move your legs enough, poor circulation may cause your legs to cramp; whether you take a short walk or break out into jumping jacks once per hour, try to get up and move every once in a while.
  1. Alcohol consumption
    • When you drink alcohol, it is absorbed in the blood and transported throughout the body—including to the leg muscles. Research shows that heavy drinking can lead to cramping by causing structural changes in the skeletal muscle.5 There are two reasons for this.
    • First, alcohol causes lactic acid—the same buildup in the muscles you experience after intense exercise—to accumulate in the body, which can cause muscle spasms and soreness.5 Second, heavy alcohol consumption has a dehydrating effect. Drinking enough water, therefore, can lessen your chances of dealing with alcohol-related cramps.
  1. Certain health conditions & medications
    • The Mayo Clinic indicates that leg cramps are linked to nerve compression, inadequate blood supply, and other factors.1 They are a symptom of a number of health conditions—mainly those that affect the nerves, liver, and thyroid.1 Leg cramps are also more common during pregnancy.1
    • Specifically, muscle spasms in the legs are tied to the following medical conditions:2
      • Cardiovascular disease
      • Cirrhosis
      • Hypothyroidism
      • Multiple sclerosis
      • Parkinson’s disease
      • Peripheral artery disease
      • Osteoarthritis
      • Type 2 diabetes
    • But leg cramps aren’t only tied to these conditions. Just as leg cramps can be symptomatic of certain health problems, they are also a side effect of certain medications. Diuretics,6 for instance, can induce cramping by causing dehydration and depleting the body of sodium and other minerals, while oral contraceptives7 and statins8 (cholesterol-lowering medications) can cause soreness in the muscles and lead to leg cramps.
    • These medications have been found to cause nocturnal leg cramps in particular:2
      • Intravenous iron sucrose (treats iron deficiency anemia)
      • Conjugated estrogens (treats symptoms of menopause)
      • Raloxifene and teriparatide (treat osteoporosis)
      • Naproxen (an anti-inflammatory drug, treats fever and pain)
    • Similarly, those who are going through withdrawal from drugs with sedative effects may also experience leg cramping for a short time. The medical reasons behind leg cramps are numerous, although muscle spasms are not always linked to medical conditions or medications. The other common culprits described earlier include: dehydration, sleep deprivation, electrolyte imbalance, intense exercise, prolonged sitting or standing, and alcohol consumption.

While uncomfortable, leg cramps generally don’t pose serious health consequences. Consult a medical professional if you are experiencing recurring or especially debilitating cramping in the legs.


  1. Mayo Clinic. Muscle Cramp. https://www.mayoclinic.org/diseases-conditions/muscle-cramp/symptoms-causes/syc-20350820. Accessed May 4, 2018.
  2. Allen RE, et al. Nocturnal leg cramps. Am Fam Physician. 2012;86(4):350-355.
  3. MedlinePlus. Muscle cramps. https://medlineplus.gov/musclecramps.html. Accessed May 4, 2018.
  4. Bergeron MF. Muscle cramps during exercise – is it fatigue or electrolyte deficit? Curr Sports Med Rep. 2008;7(4):S50-S55.
  5. Rubin E, et al. Muscle damage produced by chronic alcohol consumption. Am J Pathol. 1976;83(3):499–515.
  6. Harvard Health Publishing. Tips for taking diuretic medications. https://www.health.harvard.edu/heart-health/tips-for-taking-diuretic-medications. Accessed May 4, 2018.
  7. Thompson HS, et al. The effects of oral contraceptives on delayed onset muscle soreness following exercise. Contraception. 1997;56(2):59–65.
  8. Harvard Health Publishing. Managing statin muscle pain. https://www.health.harvard.edu/pain/managing-statin-muscle-pain. Accessed May 4, 2018.

Submitted by the Metagenics Marketing Team

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