Health Nutrition

Hydration and Running: 3 Common Mistakes

Being properly hydrated is crucial, especially for runners. In order to achieve good sports performance, it is necessary to take in the right amount of fluid and to adequately replace the nutrients lost during training. Hydration is just as important as proper nutrition and sticking to the training plan.  

Let’s find out together in our new article some information on hydration and the top 3 mistakes made by runners.

Replacing lost fluids

During exercise, every person (some more, some less) loses a certain amount of fluid through sweat. Each runner has a different rate of sweating, but this reaction of the human body coincides for everyone with a very useful biological process: the muscles generate heat during exercise, and thanks to sweating, the body eliminates it, preventing general overheating.

At the same time, sweating also means losing water and electrolytes, and it is therefore necessary to replenish them properly. Fluids in fact help the heart pump blood to the muscles, while electrolytes are essential for the performance of many body functions (we will go into the topic of electrolytes in the following paragraphs). Dehydration can create headaches, kidney problems and other medical complications. Learn more about the topic of dehydration in our article “Avoid dehydration while running – how much fluid should you consume?

First of all, it is important to drink throughout the day. Many runners only focus on fluid intake before, during or after their run, forgetting that their daily needs must be met from the morning when they get up to the evening when they go to bed.

But what is the right amount of fluid to take? A standard recommendation does not exist, as every runner has a different sweating rate and training level, as well as different speed and body. The experts’ advice is as follows: 1/2 of water two hours before training, a glass 20 to 30 minutes before, and a sip every 10 minutes during training. Finally, in the post-training phase, drink another 1/2 of water.

In the case of not very long runs (8km at the most), there is really no need to drink during the session. But when you hit 45 minutes of training, then it is advisable to drink while running. If you cannot take water with you during your run, try to organise your training on routes with access to drinking fountains. Otherwise, you can buy a bottle belt or a Camelbak.

Top 3 hydration mistakes made by runners


1. Drinking too much

After having explained that the main mistake is not drinking enough, we now show you how the opposite action can also pose a danger. Drinking too much can cause stomach problems, headaches, nausea, dizziness, drowsiness or in the worst cases hyponatriemia. The last one consists of a decrease in sodium levels in the blood caused by excessive dilution by too much liquid ingested. The salt balance is thus disturbed, leading to complications within the body. Hyponatriemia can of course also appear if the electrolytes lost through sweating are not adequately replaced.

A common myth is to think that muscle cramps are due to dehydration. You should not reason this way a priori, because the cause can also be found in simple muscle fatigue or an imbalance in terms of electrolytes. Sometimes all that is needed is to replenish the sodium lost through sweat by adding a pinch of salt in a food or drink.

Curiosity: if the runner gains weight during training, it is very likely to be overhydration.


2. Not replenishing electrolytes

The second main mistake is not adequately replacing the electrolytes lost through sweating. Studies show that during a workout, a person can lose an average of three to four litres of fluid per hour, depending on the subject’s metabolism. The main electrolytes are sodium, magnesium, calcium and potassium. These micronutrients are a crucial component in the performance of many body functions, including the proper functioning of muscles, nerves and the heart, as well as the elimination of waste products and the distribution of water in the body. It is therefore necessary to add electrolytes to your hydration strategy, because water is not enough. It is possible to consume electrolyte powders, dissolved tablets or a drink with these properties. Let’s go into the details of some of the main electrolytes:

  • Sodium

Although a diet high in sodium can be dangerous and lead to critical health conditions (hypertension), it does not mean that this element is an absolute enemy. There is a tendency to eliminate more and more salt from one’s diet, but the human being (and the runner in particular) needs this nutrient.

On average, a person loses 800 mg of sodium per litre of sweat per hour (this is an approximate figure as the rate of sweating varies greatly from person to person). Therefore, do not hesitate to add a pinch of salt to your dinner or eat salted nuts! Your blood pressure and vital functions will benefit and your body will thank you.

  • Magnesium and Potassium

Muscle function is ensured not only by sodium, but also by magnesium and potassium. These nutrients play a fundamental role, but are often not taken into account adequately. They help to restore hydration levels during the recovery phase and prevent extreme muscle cramps. A balanced diet rich in fruit, vegetables, legumes and cereals will ensure an optimal intake of these micronutrients.

The banana is a popular fruit for runners, as it is rich in potassium. Check out our summer recipe, banana and mint smoothie.

Potassium = Tomatoes, sweet potatoes, bananas, oranges, beets.

Magnesium = Seeds, lentils, leafy vegetables, broccoli, tofu, milk, yoghurt.

If you are unable to consume these foods, you may consider taking water-dispersible magnesium supplements (excessive use may have contraindications, consult a doctor before taking).


3. Too many gels but no sports drink

Finally, many runners prefer to consume gels and chews rather than sports drinks. It is true that they contain a lot of sugar, allow you to obtain the energy you need and avoid drinking or eating too much during a race, but they do not have a sufficient sodium level to maintain fluid balance. Consuming only sports gels and no electrolyte drinks could bring you closer to dehydration. We therefore recommend incorporating sports drinks into your hydration plan, which can respect the balance of micronutrients.


In conclusion, keep in mind all the advice we have given you. Drink plenty, but at the same time not too much (you can find the hydration calculator on the Swiss Sports Nutrition Society website to determine your individual fluid needs); replenish the micronutrients lost through sweating, such as sodium, potassium and magnesium; don’t disdain sports drinks and don’t overdo it with gels and chews.

Above all, listen to your body! You can tell that dehydration is starting to affect you by paying attention to certain signs: a slight headache, dark-coloured urine, muscle cramps, extreme thirst and lowered heart rate. Do not ignore the messages your body is sending you! Being too stubborn in achieving a sporting goal can sometimes be a danger to your health. If you notice a strong symptom, take a break. Balance is the key to everything.

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