Updated: October 26th, 2021

Everyone has heard of the side-stitch, most people are familiar with muscle cramps, however, it’s uncommon for most to consider an electrolyte imbalance as a muscle cramping order for concern – even throughout the athletic population. I mean, what are electrolytes? Why are they important? How do I know if they’re balanced or not? How do I replenish my electrolytes? And most importantly; how will electrolytes affect my running? (That’s why we’re here, right?)
Stay with me as I reveal all you will ever need to know about an electrolyte imbalance in runners.

What are electrolytes?

Electrolytes are electrically charged minerals in your blood, that help regulate your bodily functions. So having a lack can seriously impact your body – If you have suffered from dehydration then you know how it feels to be running low on electrolytes. There is a reason severe dehydration can cause death because of its impact on the functioning of:

  • Blood clotting
  • Muscle contractions
  • Acid balance
  • Fluid regulation
  • Heartbeat regulation

Just to name a few. I bet you’re now rethinking your last few runs, were you hydrated? How did you feel? Should you invest in a hydration belt or camel pack? Depending on your distances, personal circumstances, the answer is probably yes. Because the last thing you want to be worrying about on the road, trail or track, is whether or not you’re hydrated and that your electrolytes are balanced.

bottle of water

Putting them under the microscope, these are some of the main electrolytes (most you will have probably heard of):

  • Sodium – encourages the movement of water inside cells
  • Chloride – Teams up with sodium
  • Magnesium – important for enzyme reactions
  • Calcium – aids cell function, heart rate and blood clotting
  • Potassium – working closely with sodium also, to maintain water balance and an acid-base balance. Teams up with calcium to regulate muscle and nerve activity
  • Phosphate – helps build and repair bones, teeth, stores energy, contracts the muscle and enables nerve function.

How to know if you have an electrolyte imbalance

For your body to function properly and effectively, it needs electrolyte balance. So if you have been sweating a lot lately, or victim of vomiting and/or diarrhoea its safe to say your electrolytes can become unbalanced. Poor hydration and salt intake before exercise, having a chronic (long term) respiratory issues or if you’re on certain medications such as diuretics, laxatives, steroids, specific antibiotics and seizure medications are also causes for imbalanced electrolytes.

Symptoms of electrolyte imbalances:

  • Nausea
  • Fatigue
  • Lethargy
  • Vomiting
  • Confusion
  • Irritability
  • Headaches
  • Fast heart rate
  • Muscle cramping
  • Muscle weakness
  • Irregular heartbeat
  • Abdominal cramping
  • Numbness and tingling
  • Convulsions or seizures
  • Diarrhoea or constipation

tired runner with headache

Regarding runners – We are particularly interested in the muscle cramp symptoms – over longer distances (we’re talking marathons and ultra-marathons generally) the excessive sweating and electrolyte loss (particularly sodium and Chloride loss through sweat) as the miles continue and so does the sweating a sodium deficit can occur in the entire body (especially if you are not replacing these with a sports drink, food or capsules).

The changes in sodium levels cause electrolyte imbalance – The water inside cells is not being moved around the body as it should be, having a knock-on effect to cause neuro-muscular junctions to become hyper-excitable. Instead of switching ‘off’ or switching ‘on’ with a natural, flowing, steady stimulus, they are bombarded, resulting in muscle cramping.

And more often than not, dehydration is the underlying culprit.

Calf cramp during running

Muscle fatigue cramping vs electrolyte muscle cramping

If you’re clued up with the fatigued induced muscle cramp you’ll know that cramping is:

  • Constant
  • Sudden onset
  • Caused by prolonged excessive movement
  • Occurs in predominantly calves for runners
  • Localised to the overworked area

Whereas electrolyte imbalance muscle cramp is different:

  • Gradual onset (typically initiated by smaller muscle twitches barely visible)
  • Occurs in highly active, bigger muscle groups such as muscle group such as quadricep/hamstrings (as they are biarticulate)
  • The cramping ‘spreads’
  • Occurs bilaterally (in both hamstring groups for example)
  • Cramping is intermittent

How to treat electrolyte imbalance on the run

Why is this helpful? Well, picture this: You’re mile 20, and you experience muscle cramping, small flickers of muscle tension, you’re thirsty (because you missed the water station, it was overcrowded) and feel a bit sick.

Getting clued up and understanding the signs, symptoms causes and remedies of each type of cramping (fatigue or electrolyte) you will know how to treat it and get back on your feet and back to racing. Could it be fatigue based? Or is it electrolyte based?

What to do:

  • Immediately replenish electrolytes at the first sign of muscle twitches/cramps! Interestingly most sports drinks out there are coined ‘isotonic’ meaning they contain a carbohydrate at 6-8% A sugar concentration of that amount that is much higher than most body fluid; so it is not readily absorbed into the bloodstream, so is it aiding our hydration? (Most definitely will make any vomiting and diarrhoea worse too). By diluting the sports drink or amount of sugars (or using electrolyte substitutes) you’re providing our body with the best combination for replenishment and immediate absorption.
  • Likewise, opt for a heavily diluted version or mix a pinch of salt into a 0.5L regular carbohydrate sports drink.
  • Electrolyte water on the run

  • Alternatively, for my ultra-distances, I had a homemade sports drink: 600ml bottle filled with 1/3 fruit juice, a small helping of coconut water, and then fill the rest with water to dilute to help replenish my salts en route.
  • Success caps! Are pure electrolyte capsules filled with sodium, potassium, chloride, bicarbonate, and phosphate. As the gold standard for electrolyte replacement on the run, I can personally recommend these capsules, they’re easy to swallow, noticeable rebalance in around 10-15 Minutes. Pop one when you’re feeling uncomfortable (sloshing of liquid or cramping) at a rate of 1 per 2 hours or in excessive heat/sweating 1 for each hour of running, and you’re run will feel much more effortless than before.
  • There is also space to discuss eating foods rich in electrolytes such as spinach, potatoes, beans, avocados, oranges, bananas to help restore low electrolyte levels. So if you’re hitting the marathon or ultra distances, consider snacks that contain these foods to help the body restore electrolytes it’s losing.

Runners nutrition for electrolytes

So there we have it, another clued up runner on electrolytes. They’re too often overlooked or misunderstood; so share this article with anyone you know running 26 miles plus, you might save their race! Alternatively, save this article for later: some light reading for you closer to race day.

And as always, good luck!

As an Amazon Associate we earn from qualifying purchases

Recommended reviews

Expert score
8/10

Nike Air Zoom Alphafly Next Nature Review

The Air Zoom Alphafly Next Nature is a fast and natural-feeling super shoe ... (Read expert review)
Expert score
9/10

Asics Kayano Lite 2 Review

The Kayano Lite 2 is a lighter and more eco-friendly version of ASICS premier ... (Read expert review)
Expert score
8/10

Nike Downshifter 11 Review

The Nike Downshifter 11 is a great, people pleaser, of a running shoe. It’s ... (Read expert review)
Expert score
7/10

Nike Air Zoom Structure 24 Review

The Nike Air Zoom Structure 24 is a supportive neutral trainer which can ... (Read expert review)
Expert score
8/10

Nike Zoom Fly 4 Review

The Nike Zoom Fly 4 is the training version of the Vaporfly Next% 2 and it ... (Read expert review)
Expert score
7/10

HOKA ONE ONE Bondi X Review

The Hoka One One Bondi X is a super premium, max-cushioned trainer with a ... (Read expert review)