Posted on 13/02/2020

About the Author: Jono (old man) Rumbelow is the familiar and friendly face at Run in Bree street. You may not know, however, that he is an experienced coach and learned athlete himself. He also has some experience singing in a choir, but let’s not get into that. 

The Art of getting our Salt & Water intake horribly wrong.

Some time back, I wrote an article entitled “Please eat your salt”. I thought the time was right to revisit this considering the heat that has been present at a number of big races recently.

It wasn’t that long ago that the world went crazy and accused food manufactures of adding “too much” salt to their foods. Health organisations around the world found that high salt intakes are linked to a number of health issues such as high blood pressure, mostly referring to sedentary or minimally active people. As with everything new, the chance to make a a product to mitigate this situation presented itself and soon products of every form hit the shelves of supermarkets that were either “low salt” or “salt free”. As an athlete, however, your body needs salt to function. Thousands of athletes sweat more than the average person, developing a thin crusty layer of, yes salt, on your bodies. It may not the most flattering look in the world, but hey, you were exercising and that’s more important.

The genius mechanism that is our body, is able to maintain a finely tuned balance of salt and water when exposed to all the silly things we do in our lives like Ironman’s® or Ultra Trail races, provided we supply it with the right nutrients and minerals. Nutrition during an event is so vital and unless you have trained with that which you use in a race, you place your body under even more stress than needed. When you have the right solution you should have by default, the right mix of water, salt, electrolytes and all the other nutrients we need to race competitively.

We invariably get it wrong, however, when the going gets hot. Why? Because we all train at 5 or 6am when the race has not even started and instead of sleeping in late on a Saturday or Sunday, and in turn allowing our other half to do so as well, we lose the perfect opportunity to test ourselves in heat. In doing so we over hydrate which can lead to Hyponatremia.

What is Hyponatremia?

Hyponatremia means a low concentration of sodium in the blood. It normally happens in endurance athletes when the heat has been “switched up” but can happen at any time when you drink too much pure water and not electrolyte solutions. We worry so much about dehydration yet all the studies show that as much as the top 30% in most endurance events are dehydrated. I’m not saying don’t drink, I’m saying you need to get this right from the word go.

Hyponatremia can occur in a few ways with the most common being dilutional hyponatremia. This is when you take in too much fluid without the correct balance of minerals, resulting in the sodium (and other electorlytes) to become diluted. . The nutrients we take in end up in our blood stream which feed our muscles that are hard at work, but forget the salt and “Houston, we have a problem”. When it is hot, this problem would be fast-tracked as more salt is lost in sweat per hour than is usually replaced by food and fluids, including sports drinks when the temperature is more than that which we can handle. Your body can tolerate a degree of imbalance for a short period of time, but it may decompensate if this continues for too long. Sweat contains between 2.25 – 3.4 grams of salt per litre, and the rate of perspiration in a long, hot race can easily average 1 litre per hour (athlete dependant). So, for a 12 hour race, one could lose approximately 27 to 41 grams of salt. If the athlete replaces only the lost water and has minimal salt intake, hyponatremia can result.

Why is Hyponatremia dangerous?

This is not a situation that you want to get into and to those of you who think that it’s ok to take all those “anti – inflammatory” tabs to help with the pain during the run (which I don’t recommend) , just remember this interferes with kidney function and this can add to you getting hyponatremia. The indications that you could have it, range from mild to severe. They include nausea, muscle cramps, disorientation, slurred speech, confusion, and inappropriate behaviour. As it progresses, victims may experience seizures or coma, and death can occur. Severe hyponatremia is a true medical emergency.

Tips to avoid it?

It cannot be stressed enough that you have got to know what your needs are prior to race day. Rehearse your hydration, feeding, and salt strategy during your training sessions. There are so many variations between individuals that there is no single right answer. You need to get to know your body and to help you achieve that, here are a few simple tips

  • Drinking at the first signs of being thirsty is the perfect way to to attempt to stay hydrated in training and event. Recommendations for drinking during a training/race is to ‘drink to thirst’.
  • During a long, hot race, aim for a total sodium intake of approximately 1 gram per hour, as recommended by Doug Hiller, M.D. (from experience with the Hawaii Ironman®. Please note that this may not be appropriate for everyone.)
  • During training, heat acclimatisation, and for several days leading up to a big race make sure that you ensure appropriate salt intake (± increase in intake by 10 – 25 milligrams per day)
  • Avoid aspirin, ibuprofen, or other anti-inflammatory tablets
  • Check with your doctor if you have any health problems


Have you ever had a situation where you’ve been over hydrated? Or do you have any tips of your own for feeding and hydration strategies during a race? We love to hear from you, so leave your comment below!

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