How to Avoid Muscle Cramping

Muscle Cramping during Exercise

It is estimated that the vast majority of athletes have suffered from cramping at some point. 

Muscle cramps are very common, affecting between 40 and 95 per cent of athletes at some point (depending on which survey you read). As a result, they have been widely studied, yet no one really knows the full story about why they occur.

Here are some theories on what causes cramps, and tips on how to avoid muscle cramping during exercise.

Definition of muscle cramp

The dictionary defines muscle cramp as “The sudden, involuntary, spasmodic contractions of selected muscles”.

What causes exercise-associated cramps?

There are essentially two competing theories of what causes Exercise Associated Muscle cramps.

The “Dehydration/Electrolyte Theory”

This theory speculates that a significant disturbance in fluid or electrolyte balance, usually due to a reduction in total body exchangeable sodium stores, causes a contraction of the interstitial fluid compartment around muscles and a misfiring of nerve impulses, leading to cramps.

In simpler terms, if you lose a lot of sodium and don’t replace it (as is common when you sweat a lot), this can cause fluid shifts in the body that in turn causes your muscles to cramp up.

The “Neuromuscular Theory”

This theory is more recent and proposes that muscle overload and neuromuscular fatigue are the root causes of Exercise Associated Muscle Cramp. The hypothesis is that fatigue contributes to an imbalance between excitatory impulses from muscle spindles and the Golgi tendon’s inhibitory impulses, resulting in a localized muscle cramp. 

In other words, muscles tend to cramp specifically when they are overworked and fatigued due to electrical misfiring.

One big factor that does appear to support the neuromuscular theory is that stopping and stretching affected muscles is a pretty universally effective method to fix a cramp when it is actually happening. What stretching does is put the muscle under tension invoking afferent activity from the Golgi Tendon Organs (part of the muscle responsible for telling it to relax) and causing the cramp to dissipate.

The Salt Deprivation Study

The first is a classic study on salt depletion that was carried out by a pioneering doctor – R.A McCance – in the 1930s. McCance was a hands-on type of researcher and was intrigued by the question of what would happen to the human body if it was depleted of salt but not fluid (numerous studies into dehydration had already been undertaken by then). He organized a study using himself and a couple of colleagues as test subjects.

Essentially what McCance and his co-workers did was subject themselves to an incredibly low salt diet. Along with their salt-free food, the subjects drank plenty of water and took hot baths to increase sweat output and accelerate salt loss. They found that when salt depletion started to kick in it quickly led to…

 “…aberrations of flavour, cramps, weakness, lassitude, and severe cardio-respiratory distress on exertion.”

Interestingly, as soon as the test subjects reintroduced salt into their systems (eating bacon and drinking the fat from the pan I might add) their recovery from symptoms – including the absence of further cramping – was ‘dramatic’ with effects being felt within 15 minutes of ingestion of the salty meal.

This experience in particular is congruent with lots of other anecdotal evidence coming from athletes who train or compete in similar conditions of heavy sweat loss

Hyponatremia and Cramp

Another notable example of electrolyte disturbance associated with cramping can be found in case reports of people suffering from hyponatremia, especially when this occurs around exercise.

Hyponatremia is a condition where blood sodium levels fall lower than they should be due to dilution by overconsumption of water, excessive loss of sodium from the body, or both together as is common amongst athletes.

Cramping is often listed as a general symptom of hyponatremia in medical texts and there are case study reports in the literature such as one involving a UK serviceman who suffered cramps and collapsed whilst running in the heat in Saudi Arabia in 1991. He has successfully treated with an intravenous saline (salt) solution and made a full recovery in the short term, but was later found to have undiagnosed Cystic Fibrosis (CF) – a condition in which sufferers lose very large amounts of salt in their sweat.

It seems likely that this high rate of salt loss could have predisposed him to lose more salt than others doing the same exercise (who did not cramp and collapse) and contributed to him suffering cramps and fatigue on more than one occasion when exercising in hot conditions.

Aside from this individual case, it’s well known that CF sufferers can struggle with exercise in the heat, at least in part due to their elevated levels of salt and fluid loss through very salty sweating.

Cramp Anecdotes from the Real World

The bottom line is that there are a lot of examples out in the real world of people losing a lot of salt (often via sweating) and suffering cramps as a result and that, very often, increasing their intake of salt (or sodium in other forms) seems to provide relief, or even prevents cramps from happening in the first place.

Of course, the big problem with case studies, observations and anecdotes is that they can fail to paint a truly complete picture of what is really going on because they can be influenced by bias, lack control groups and can fail to account for the placebo effect. 

What is the placebo effect? The placebo effect is when a person’s physical or mental health appears to improve after taking a placebo or ‘dummy’ treatment. Placebo is Latin for ‘I will please’ and refers to a treatment that appears real but is designed to have no therapeutic benefit.


It has also been pointed out that not all cramps can be traced back to sodium loss (think about cramps that occur in cool conditions or at times when sweat losses are not significant) and that not all cramps respond to increased sodium intake. This is one big reason that the Neuromuscular Theory has been developed to try to fill in the gaps where sodium loss does not provide an adequate explanation for what is likely to be going on.

How to Alleviate the Symptoms of Cramp

One thing that makes cramping so difficult to understand is that it remains a stubbornly fickle and unpredictable phenomenon to pin down and study properly. This is one reason why evidence for both the Dehydration/Electrolyte theory and the Neuromuscular theory is often not as robust as it could be.

A 2019 review paper argues that there’s no definitive cause of cramps, but rather different causes for different types of cramps. The authors suggest it isn’t necessary to know the cause to find a treatment and maybe more time and energy need to be spent trying to treat/prevent cramps.

The bottom line appears to be that muscle cramps are likely to have multiple causes including, but not limited to, electrolyte imbalances and neuromuscular fatigue and that, as a result, multiple interventions are likely likely to be needed to try to eliminate these ‘different flavours’ of cramp. At Precision Fuel & Hydration we surveyed hundreds of athletes who reported suffering from cramps and more than 85% of them had tried more than one method in an attempt to alleviate the issue.

Does pickle juice fix the cramps?

In the last five years or so (and somewhat connected with the rise of the neuromuscular theory) there has been a lot of interest in the use of compounds that can stimulate something in the mouth called ‘transient receptor potential (TRP) channels and the possible effects these might have on cramping muscles.

TRP channels connect the mouth to the central nervous system. The hypothesis is that stimulating these receptors somehow causes a ‘jolt’ reaction down the nerves that disrupt the signals causing a cramp.

Substances that stimulate TRP channels are things like wasabi, mustard oil and other pungent spices and it’s thought that this is where the idea of using pickle juice to cure muscle cramps (a common practice in the USA in particular) comes from. Pickle juice contains acetic acid and it’s believed to be this (rather than the high levels of sodium in it) that stimulates the TRP receptors and helps relieve cramps.

This would explain why cramps have sometimes been shown to be relieved almost instantly when pickle juice is ingested (the nerve stimulation happens almost instantly, whereas the sodium in it takes several minutes to travel to the gut and to be absorbed into the blood). It’s also consistent with the general idea that the root cause of some cramps is found in the nervous system rather than solely an electrolyte imbalance. 

How to Avoid Muscle Cramping During Exercise

There’s no “magic bullet” available to kill off muscle cramping at the moment and it doesn’t look like there will be one coming anytime soon.

However, if you’re not inclined to sit around twiddling your thumbs waiting for science to deliver in its own sweet time, there are a few things you might want to try if you suffer from EAMC.

1. Try reducing fatigue.

  • Because it seems highly likely that fatigue is also implicated in muscle cramping during exercise, finding ways to minimize this is also logical. As obvious as many of them may sound, try to make sure you tick all of the following boxes to ensure you’re not overloading your body excessively:
    Train specifically for the event(s) that tend to induce cramps, i.e. with the right mix of volume and intensity to prepare your muscles for what is going to be asked of them.
  • Pace yourself appropriately based on fitness levels and environmental conditions to avoid overloading muscles prematurely.
  • Taper into events so that you are fresh and well-rested when you start.
  • Make sure you’re adequately fuelled with plenty of carbohydrates on board before you start events and that you fuel adequately during activity to avoid becoming glycogen depleted (which can contribute to premature fatigue).

2. Try consuming additional sodium.

This is definitely a good idea if your cramps tend to occur during or after periods of heavy sweating, in hot weather, later on during longer activities, or if you generally eat a low sodium (or low carb) diet.

One note of caution: if you do take on additional sodium, especially in the form of electrolyte drinks, make sure they are strong enough to make a real difference. Most sports drinks are extremely light on electrolytes (despite the claims they make on their labels), containing only about 300 to 500 mg sodium per litre (32oz).

Human sweat, on average, comes in at over 900 mg of sodium per litre (32oz), and at Precision Hydration we often measure athletes losing over 1,500mg per litre through our Advanced Sweat Test. It’s therefore a good idea to look for upward of 1000mg sodium per litre in a drink and over 1,500mg per litre if you suspect you are a particularly salty sweater. A good way to see where this should fit into the rest of your hydration strategy is by taking this free online Sweat Test.

If you’re consuming salt or sodium separate from your fluids, in foods or capsule form, aim for a similar ratio (i.e. 1,000-1,500mg sodium along with each litre of water you drink) and remember that table salt (NaCl) is only 39 per cent sodium (the other 61 per cent is chloride), so you need about 3g of salt to give you about 1,170mg of sodium.

Take the extra sodium in the hours immediately before and during activities that normally result in cramping and see how you get on. You’ll know pretty quickly if this is effective, and you can fine-tune your dosage to balance cramp prevention with keeping your stomach happy over time (excessive salt or sodium intake can cause nausea).

Other strategies

Other strategies that are far from proven, but that either make intuitive sense or have been used by athletes in the war on cramps include:

  • Sports massage and stretching of the affected muscles
  • Acupuncture
  • Thorough warm-ups before cramp-inducing activities
  • Mental relaxation techniques

Although none of these is likely to offer a complete solution, they are generally accessible, inexpensive and may even benefit performance in other ways, so there would seem to be little downside to giving them a try.


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