How to avoid cramp during exercise - Precision Hydration guest blog

Blog - How to avoid cramp during exercise - Precision Hydration guest blog

How to avoid cramp during exercise - Precision Hydration guest blog

7 minute read

For a lot of people, this time of year is the start of event season, with a lot more of you getting out there and getting active. It's a good time to think about your training and preparation for events, so we wanted to take a look an aspect of this which affects a lot of athletes. Muscle cramps are a common event-ruiner for many of us; between 40 and 95% of athletes are affected by cramp at some point depending on which survey you read.

So we asked our friends at Precision Hydration to tell us a bit more about why we might be cramping up and to share some tips on how to avoid them…

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So, just why do you cramp up during exercise?!

There are two main theories on what causes cramp…

1) Dehydration and an electrolyte imbalance

This theory suggests that if you lose a lot of sodium and don’t adequately replace it (as is common when you sweat a lot) fluid shifts in your body trigger cramps as the interstitial fluid compartment around your muscles contract, causing a misfiring of nerve impulses.

This idea is based on plenty of case studies, observational data, anecdote and expert opinion (what scientists call ‘level 4 and 5 evidence’). One such study documented a case study of a tennis player who often suffered with cramp during tournaments. The player had a high sweat rate and was deemed unlikely to be replacing his sodium losses via his normal diet, so he was prescribed an increased salt intake.

The conclusion of the study was that “[The Player] was ultimately able to eliminate heat cramps during competition and training by increasing his daily dietary intake of sodium.”

This tallies with our experience at Precision Hydration. We conducted a survey of athletes who had reported suffering with muscle cramps during exercise and 90% of respondents said that they had found that supplementing with sodium or salt during exercise had helped them reduce or eliminate the problem.

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2) Neuromuscular fatigue

The other major theory behind cramp suggests that muscle overload and neuromuscular fatigue are the root causes of the issue. The hypothesis is that muscles tend to cramp specifically when they are overworked and fatigued due to electrical misfiring.

The fact that stopping and stretching affected muscles is a often a very effective way to fix a cramp lends support to this theory. 

It’s likely that that both electrolyte imbalances and neuromuscular fatigue are triggering cramp (both on separate occasions and when occurring at the same time). It’s likely that you’ll have been sweating and working hard for long periods of time anytime you’re wearing your dryrobe, so both of these factors could be contributing towards your cramps.

As a result, it’s likely that multiple interventions are needed to try to reduce and eliminate the problem. In our survey, 93% of athletes had tried more than one method in an attempt to get on top of their cramps.

Ok, so how do you avoid cramping up?

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.

But, if you’re not inclined to sit around twiddling your thumbs waiting for science to deliver in it’s own sweet time, there are a few things you might want to try…

1) Guard against premature fatigue

As obvious as many of these suggestions 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 event(s) that you tend to cramp up in - i.e. with the right mix of volume and intensity to prepare your muscles for what’s 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. Ensure you have plenty of carbohydrates on board before you start and that you fuel adequately to avoid becoming glycogen depleted which can contribute to premature fatigue.

2) Try consuming additional sodium before/during/after events

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

You can do this by eating salty food, or adding salt to your food but remember that table salt is only 39% sodium (the other 61% is chloride), so you need ~3g of salt to give you ~1,170mg of sodium.

An easier (and more measurable) way to get extra sodium in is through an electrolyte drink (or capsule supplement). But, just make sure your drink is 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 200-500mg of sodium per litre (32oz).

But, the average human loses about 950mg of sodium per litre (32oz), and at Precision Hydration we often measure athletes losing more than 1,500mg per litre (including myself) through our Advanced Sweat Test. So, it’s a good idea to look for drinks containing at least 1,000mg of sodium per litre and over 1,500mg per litre if you suspect you’re a particularly ‘salty sweater’. A good way to see how this should fit in to the rest of your hydration strategy is by taking this free online Sweat Test.

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 or not, and can fine tune your dosage to balance cramp prevention with keeping your stomach happy over time (really excessive salt or sodium intake can cause nausea).

When I first started taking in additional sodium before and during long, hot triathlon races the effect was immediate and dramatic. I went from cramping up almost every time, to almost never having problems again.

I ended up settling on a regime of consuming around 1000-1500mg of sodium per hour during long races (I lose a lot of salt in my sweat, ~1,800mg/l in fact) and also found that taking this amount eliminated post-race cramping almost entirely as well.

If you want to give Precision Hydration’s stronger electrolyte drinks a try, use the code DRYROBE to get a free box or tube worth up to £9.99 ($13.99). And email us at if you have any questions at all about your hydration strategy.

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3) Experiment with other popular ‘cures’ for cramp.

Many of these are far from proven, but either make intuitive sense or are commonly used by athletes include…

• Sports massage and stretching of the affected muscles.

• Acupuncture.

• Thorough warm ups prior to cramp inducing activities.

• Mental relaxation techniques.

• Drinking pickle juice. (Cramps have sometimes been shown to be relieved almost instantly when pickle juice is ingested).

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

Hopefully this overview of the major theories on what causes muscle cramp have left you feeling better equipped to fight your own war on cramp!

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Andy Blow has a degree in Sport and Exercise Science and was once the Team Sports Scientist for Benetton and Renault F1 teams. He has a few top 10 Ironman and 70.3 finishes and an Xterra World Age Group title to his name. He founded Precision Hydration to help athletes solve their hydration issues. He wears a custom Precision Hydration dryrobe at every event.