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Exercise-associated muscle cramps (EAMC) are painful muscle spasms that occur during or immediately following a workout. They are spawned by an involuntary contraction of a muscle that will not relax. Muscle cramps typically start in the leg—often in the calf muscles (i.e. the dreaded Charley horse). But they also can occur in any of the body’s skeletal muscles (muscles moved under your voluntary control).
EAMC is a poorly understood problem, although there are a variety of hypotheses as to the root cause. Below, we offer 13 factors that can prompt muscle cramps.
13 Most Common Causes of Muscle Cramps
There are several reasons nerve signals to the muscles malfunction and involuntary muscle contractions (along with painful cramping) ensue:
- Poor blood circulation
- Poor diet (not enough glucose during exercise)
- Back problems or back injury
- Mineral depletion and lack of electrolytes (calcium, magnesium, sodium or potassium)
- Having long periods of high adrenaline (fight or flight hormone)
- Overuse/general muscle fatigue, which can be caused by standing or exercising too long, putting extra pressure on your leg muscles
- Being active in hot weather
- Lack of proper warm-up or stretching post exercise
- Kidney or thyroid disorder (affects fluid levels)
- Side effect of certain medications (cholesterol-lowering drugs called statins, asthma medications, high blood pressure medications, or diuretics)
Does Dehydration Really Cause Muscle Cramps?
Of the 13 causes of muscle cramps listed above, most sports enthusiasts will swear that dehydration is the primary culprit; however, recent evidence suggests otherwise. Exercise-associated muscle cramps may more likely be caused by a condition known as “altered neuromuscular control.”
This theory stems from laboratory-based experiments that used an EMG to monitor spinal reflex activities in response to muscle fatigue and cramping. (EMG stands for electromyography, a diagnostic procedure to assess the health of muscles and the nerve cells that control them called motor neurons.) The researchers proposed the underlying cause of the altered neuromuscular control is due completely to muscle fatigue, heat, and decreased energy (nutrition) supply:
“There are several disturbances, at various levels of the central and peripheral nervous system, and the skeletal muscle that contribute to cramping. These disturbances can be described by a series of several key events. First and foremost, repetitive muscle exercise can lead to the development of fatigue due to one or more of the following: inadequate conditioning, hot and or humid environments, increased intensity, increased duration, and decreased supply of energy.
“Muscle fatigue itself causes increased excitatory afferent activity within the muscle spindles and decreased inhibitory afferent activity within the Golgi tendon. [The Golgi tendon organ is a sensory receptor that plays a key role in the reflex regulation of muscle contraction.] The coupling of these events leads to altered neuromuscular control from the spinal cord.
“A cascade of events follow the altered neuromuscular control; this includes increased alpha-motor neuron activity in the spinal cord, which overloads the lower motor neurons, and increased muscle cell membrane activity. Thus, the resultant of this cascade is a muscle cramp.”
In other words, the research demonstrates that altered neuromuscular control from muscle fatigue and decreased energy supply seems more plausible in explaining many of the unanswered questions with regard to the cause, treatment, and prevention of cramping.
How to Prevent Muscle Cramps
Now that you know the primary causes of muscle cramps, it’s time to focus on how to get rid of this pain!
1. Drink water, but start drinking before you begin exercising.
Water will not help after muscle cramps have already started. A study in the Journal of Science and Medicine in Sport revealed that water intake after dehydration and during exercise make muscles more susceptible to cramping, most likely due to a dilution of electrolytes. However, when consuming fluid containing electrolytes, the susceptibility to muscle cramps decreases. Which leads to treatment #2….
2. Drink sports drinks beverages.
Yes, these drinks are loaded with sugar, but they also contain the proper balance of sodium, magnesium, and potassium needed during high-intensity or long-endurance sports. The problem with sports drinks is that many people consume them when they’re not exercising—which is not the intended use for this type of beverage. Drinking too many sugar-laden beverages can lead to weight gain or other health issues such as diabetes. Therefore, you should drink sports drinks only before, during, or immediately after periods of exercise.
3. Take electrolytes.
You can take electrolyte pills in place of sports drinks. However, if you take this route, know that your body will also require a certain amount of glucose (sugar) to sustain energy levels. So if you opt for electrolyte pills, be sure to eat high-carbohydrate snacks before and during exercise.
4. Consume TRPs.
“TRP” stands for transient receptor potential channel agonists, a group of ion channels located on the plasma membrane of numerous animal cell types. Specifically, studies show a group of TRP channels called TRPV1 agonists help with muscle cramps. So, what in the world are these TRPVI agonists? We’ll spare you the chemistry—simply put, these are molecules found in such spices as:
- Garlic (allicin)
- Chili pepper (capsaicin)
- Wasabi (allyl isothiocynate)
- The cactus plant E. resinifera (resiniferatoxin)
- Other molecules activated by menthol, camphor, or peppermint
You can take garlic, chili pepper, or peppermint capsules to prevent or stop exercise-induced muscle cramps. It’s also a good idea to drink a stevia-sweetened beverage before exercising. Last, if muscle cramps do start, use a natural menthol, camphor, or peppermint oil or cream to rub on your pain spots.
5. Walk backwards.
If you begin experiencing cramps in the back of your legs (calf or hamstring muscles), turn around and walk backwards. Walking backwards will change the reactions and demands on the leg muscles and stimulate tissue lengthening and muscle imbalance correction. In fact, many endurance athletes and runners have noticed that simply walking backwards is enough treatment to completely stop leg cramps in their tracks.
 Scientific Pages Sports Med. 2017; 1(1):3-14
 Journal of Science and Medicine in Sport, 2017. 20S;S164-S166.
 Muscle & Nerve. 2017; 56(3): 379-385.
 Br J Pharmacol. 2014 May; 171(10): 2474–2507.
 FASEB Journal. 2016 April; 30(1).