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Leg and Calf Cramps From Running – ( Explained) The Best Science of Muscle Cramps

calf cramps from running

What causes leg or calf cramps from running?

Calf muscle cramping from running or other exercise is thought to be different than the night-time cramping that some older adults experience.

A muscle cramp is an involuntary contraction of a muscle and results in pain and temporary loss of muscle function since the muscle can’t be lengthened until the cramp subsides.

There have been many theories regarding the cause of muscle cramping during running, from dehydration to electrolyte abnormalities to training issues. 1

Further research on the cause of muscle cramping has down played the role of electrolytes 2 in favor of electrical over-stimulation of the muscle and the inability of the Golgi tendon structure to inhibit this over-excitation, resulting in the contraction and cramping of the muscle. 3

What causes leg muscle cramps on keto?

Some runners may be experimenting with low-carb diets like the ketogenic diet and also find that they experience more leg muscle cramps while on a ketogenic diet. One reason for the increase in calf muscle cramping may be attributed to changes in electrolyte imbalances from the lower carbohydrate diet and improved insulin sensitivity. As the body becomes more insulin sensitive due to much lower carbohydrate intake, the kidneys hold onto less sodium.

Adding more table salt to the diet as well as eating foods higher in magnesium like nuts and seafood, can help prevent significant drop in magnesium, sodium and potassium levels while on a ketogenic diet.

How to treat and relieve calf cramps from running

If you get calf cramps from running, the best option is to stop running and try to slowly stretch the muscle until the cramping stops. Be sure to carefully hold the stretch until the cramping resolves and remember not to bounce or overstretch the muscle or the muscle cramp may return.

After the muscle cramp has resolved, try jogging slowly to see if the muscle cramps will return.

Can dehydration cause calf cramps from running?

Staying hydrated is one problem many runners face, especially when running during the hotter and more humid summer months. If you don’t keep up on your fluid intake while running, dehydration can make you more prone to leg and calf cramps from running. However, dehydration is only one potential cause of calf cramping.

It’s also important to not only replace the fluids, but the electrolytes such as sodium that you also lose from sweating. Make sure that your sports drink has the proper balance of sodium and potassium.

Can low sodium, potassium, or magnesium prevent leg or calf cramps from running?

There has been a lot of research on electrolytes such as sodium, potassium, and magnesium and their impact on muscle cramps from running and other exercise activities. 4 5 While the research is still split between electrolyte imbalances, dehydration, and the neuromuscular component for cramping, I have had many runners and triathletes that find their leg and calf cramps are significantly reduced when they make sure they are getting enough sodium, potassium, and magnesium in their diet.

Runners that are low in magnesium may require a daily magnesium supplement like Slo-Mag once or twice a day to replenish their level

Pickle Juice to stop calf cramps

I’ll admit, the first time I heard or saw about pickle juice as a potential treatment for muscle cramps, I was watching a college football game and one of the trainers had a few players drinking pickle juice from a pickle jar. Honestly, I thought it was one of the most “voodoo” sports medicine treatments I had seen in a long time (and I’ve seen and heard a lot of crazy ones). Admittedly, a lot of the initial comments on why pickle juice helped muscle cramps were thought to be due to the high sodium content in the pickle juice. However, recent has shown that it can take upwards of thirty minutes for pickle juice to leave the stomach and enter the small intestine where the sodium would be absorbed 6.

Pickle juice may help stop calf cramps from running because the intense saltiness of the pickle juice causes a noxious neurochemical reaction in the mouth (possibly due to the vinegar and not the salt content of pickle juice) that may interrupt the neuromuscular excitation of the cramping calf muscle.

Improving leg strength to help with calf cramps from running

Since one theory about muscle and calf cramps from running focuses on muscle fatigue, one prevention measure for runners would be to add weight and strength training along with your run training. The strength training program for runners could improve neuromuscular recruitment of muscle fibers and help prolong time to fatigue from running.

When to see your doctor about leg cramps

It’s time to see your doctor if you keep having recurrent leg cramps that don’t respond to stretching or adding extra electrolytes to your diet or if you notice any of the following conditions:

  • Muscle cramps with muscle weakness
  • Muscle cramps and bruising
  • Muscle cramps and leg swelling
  • Muscle cramps and back pain
  • Muscle cramps and pain with walking that goes away with rest, but returns when you resume walking.

Also, if you notice muscle weakness, atrophy (decreased muscle bulk) or numbness in the muscle, its also time to see your doctor.

If you start having calf cramping and pain with walking and then goes away when you rest, and returns when you start walking again, you should see your doctor to be evaluated for claudication. Claudication is a blockage of the blood flow in the legs and the reduced blood flow to the leg muscles causes ischemic pain in the legs.


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