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Isotonic drinks for trail running: stay well hydrated for better performance

Drinking an isotonic drink during a trail run is an excellent practice if you want to limit fatigue and boost your performance. As the kilometers accumulate, good hydration becomes essential to preserve your endurance and support your muscles over time.

That said, this drink must be consumed in a specific way depending on the stage of the race and the intensity of the effort to maximize its effects on your body.

In this article, you will discover the advantages of isotonic drinks in trail running, the list of ingredients to prepare it yourself, as well as the quantity to consume depending on the distance covered.


Why consume an isotonic drink during a trail run?

During a trail run, the body is subjected to significant stress. To cope with this, the consumption of an isotonic drink is highly recommended.

Compensate for fluid and electrolyte losses

Prolonged effort leads to significant fluid and electrolyte losses. In other words, you lose water and minerals that are essential for maintaining fluid balance and the muscle contraction capacity.

Without an adequate intake of water and electrolytes, the runner is exposed to cramps, a drop in performance, or intense muscle fatigue. Consuming an isotonic drink precisely allows you to compensate for these losses and prolong performance.

Optimize endurance and delay fatigue

Isotonic drinks contain sugar which will provide a quick boost to the body when it is subjected to significant energy loss during exercise.

This not only allows you to quickly replenish your energy reserves but also to maintain a stable energy level over time.

Maintain stable blood sugar levels during exercise

During the race, the body produces energy by rapidly drawing on its glycogen reserves. If these reserves are depleted too quickly, blood sugar drops. This situation generally causes fatigue, a drop in concentration, or even a decrease in performance.

Thanks to their supply of simple and complex carbohydrates, isotonic drinks release energy gradually. They thus help maintain stable blood sugar levels during the trail.

Aid in the elimination of metabolic waste

During the trail, your body produces various metabolic waste products such as lactate (lactic acid), carbon dioxide, urea, and ammonia. By consuming an isotonic drink, you hydrate yourself and, at the same time, facilitate their elimination.

This elimination, mainly ensured by the kidneys, limits the accumulation of toxins in the body and reduces the risks of nausea, headaches, and the heavy leg sensations that generally occur during exercise.


Ideal composition of an isotonic drink for a trail run

To understand the effectiveness of an isotonic drink during a trail run, it is important to look at the list of ingredients that compose it.

Simple and complex carbohydrates for energy

An effective isotonic drink combines simple and complex carbohydrates for optimal energy supply during exercise.

Complex carbohydrates, also known as slow sugars, provide a continuous supply of sugar and allow the body to maintain a stable energy average.

Simple carbohydrates or fast sugars, such as sucrose and dextrose, are rapidly assimilated and act as an energy booster with each sip. This mixture thus produces a drink that effectively supports the athlete throughout their race.

Key electrolytes: sodium, potassium, magnesium

Electrolytes are essential elements in an isotonic drink. They help compensate for losses due to perspiration and maintain fluid and muscle balance, especially during prolonged efforts. This list of minerals includes:

  • Sodium (300 to 500 mg/L): sodium promotes water retention in cells and limits the risk of dehydration. It also plays a key role in nerve transmission and muscle contraction;
  • Potassium (150 to 250 mg/L): its role is to support muscle function and prevent the onset of cramps;
  • Magnesium (20 to 50 mg/L): present at a ratio of 20 to 50 mg/L, magnesium reduces neuromuscular fatigue and participates in cellular energy production;
  • Chloride (200 to 400 mg/L): as for chloride, it helps maintain acid-base balance and complements the action of sodium for effective hydration.

Natural ingredients: honey, lemon, green tea, mint

To enrich an isotonic drink and provide it with additional benefits, certain natural and organic ingredients can be added.

Honey provides a natural dose of rapidly assimilable carbohydrates, while lemon and other fruits provide essential vitamins and minerals.

There is also green tea and mint which contribute respectively to antioxidant intake, and freshness during exercise.


What quantity of isotonic drink to consume according to the trail distance?

The quantity of isotonic drink to consume varies according to the distance and the intensity of the efforts made. Properly managing this intake will allow you to boost your performance and optimize your nutrition during the race.

Short trail (10 to 20 km): light and targeted hydration

Even over a reduced distance (10 to 20 km), a short trail remains an intense exercise. To avoid energy failure, you can carry an isotonic drink in a water bottle or flask.

Thus, you can adjust the dose according to the duration of the effort and your nutritional needs. The recommended average is 500 ml to 1.5 liters of drink. Opt for a light sugar ratio to avoid any digestive discomfort if the race lasts less than 1h30.

Medium trail (20 to 80 km): active hydration strategy

For a medium trail, nutritional and energy needs are greater. It is recommended to provide approximately 500 ml to 1 liter of drink per hour of effort, to maintain an optimal ratio between water, electrolytes, and energy carbohydrates.

Use a container of 1.5 to 2 liters, such as a camelback, as well as a flask or a flexible cup for refreshments. Adjust the consumed dose according to your rhythm and the climatic conditions.

Ultra-trail (80 km and +): structured protocol with replenishment

In the case of an ultra-trail, nutrition and hydration become strategic elements. It will therefore be necessary to precisely plan the quantity of drink per hour (between 600 and 800 milliliters) and adjust it according to temperature, altitude, or the intensity of the effort.

To limit the risks of nausea or extreme fatigue, it is recommended to plan several different energy drinks:

  • A neutral-tasting drink such as water,
  • A slightly salted version,
  • A fruit-based version,
  • Broths.

These options allow for varying the intake of vitamins, electrolytes, and energy carbohydrates.


Homemade recipe for a natural honey isotonic drink

If you want to avoid buying often expensive isotonic drinks on the market, it is possible to create your own preparation from a list of natural and organic ingredients.

Isotonic drink recipe for a short trail run

For a short trail run, here is a recipe to prepare and adapt to your tastes and preferences:

List of ingredients

  • Between 30 and 70 g of sugar (sucrose), adjusted according to temperature and intensity of effort, to provide rapidly assimilable carbohydrates,
  • One cup of green tea, enhanced with lemon or vanilla, for an intake of antioxidants and beneficial minerals,
  • A pinch of salt, essential to compensate for electrolyte losses and support muscle contraction,
  • Cold or lukewarm water to complete the drink and ensure good hydration.

Preparation

Here are the steps to follow for preparation:

  • Dissolve the sugar in the flavored green tea.
  • Add a pinch of salt to maintain electrolyte balance.
  • Top up with water to achieve the desired quantity and let cool in the refrigerator.

You can replace the tea and sugar with 50 cl of fruit juice and top up with 50 cl of water, for a fruitier and more natural version.

Isotonic drink for a long trail run (more than 2 hours)

For a long trail run, you will need to adapt your drink and nutrition to continuously provide the energy, electrolytes, and vitamins necessary for endurance and performance.

List of ingredients

  • 30 to 40 g of maltodextrin: provides complex carbohydrates for a progressive energy supply and compensates for glycogen losses during prolonged efforts;
  • 30 to 70 g of sugar (sucrose) depending on temperature: provides an immediate energy boost to sustain effort intensity and maintain stable blood sugar;
  • 1 liter of water or tea: forms the base of the drink;
  • 1 pinch of salt: provides essential electrolytes for muscle maintenance and fluid balance;
  • Optional: 50 cl of fruit juice: for a smoother and organic version, providing vitamins, minerals, and a pleasant taste, while contributing to overall energy intake.

Preparation

  • Pour the maltodextrin into the water or tea and mix.
  • Add the sugar or syrup and the pinch of salt.
  • For a fruity version, replace the sugar with 50 cl of fruit juice and top up with 50 cl of water.
  • Keep refrigerated and consume within 24 hours.


How to properly use your isotonic drink during a trail run?

The effectiveness of an isotonic drink in trail running relies not only on its composition, but also on how it is consumed. Depending on the stage of the race, your energy, electrolyte, and hydration needs will vary.

Before the race: light fluid intake

It is advisable to drink between 300 and 500 ml of isotonic drink (fractionated into small quantities of 100 to 150 ml every 30 minutes) within two hours before the start. This light fluid intake helps to replenish water and electrolyte reserves.

During the effort: fractional absorption, avoid sudden intake

During the race, it is important to drink regularly, in small sips every 10 to 15 minutes, rather than consuming large quantities at once.

This fractionation prevents digestive problems and helps maintain a constant energy supply. The goal is to stay in an optimal hydration zone throughout the effort.

After the effort: rehydration and optimized recovery

The period immediately following the finish is important for recovery. An isotonic drink consumed within hours after exercise (the metabolic window) helps to replenish glycogen stores, compensate for mineral losses, and facilitate the elimination of metabolic waste.


Should you always use an isotonic drink in trail running?

The use of an isotonic drink in trail running depends primarily on the duration and intensity of the effort. For short outings or those performed at low intensity, water alone is generally sufficient to maintain good hydration.

However, when the effort exceeds one hour, especially in hot conditions or during sustained pace, the benefit of an isotonic drink becomes obvious.


Common mistakes to avoid with an isotonic drink in trail running

However, there are a few common mistakes to avoid if you want to prepare or consume an isotonic drink during exercise:

  • Using too much fructose: This can cause digestive problems or a laxative effect during exercise.
  • Adding excessive salt: This action can have the opposite effect to what is desired and accentuate dehydration;
  • Avoiding overloading the drink with glucose: An excess of sugar in your drink can lead to a blood sugar spike, followed by reactive hypoglycemia. Above all, it risks causing gastric problems if your digestive system is not well prepared for such a concentration.

 

Your questions about isotonic drinks in trail running

Why are drinks called isotonic?

They are called isotonic drinks because they contain the same concentration of dissolved substances (sugar, sodium, potassium, etc.) as that of blood. This promotes faster absorption during exercise.

Is it possible to prepare an isotonic drink the day before?

Yes, but it must be kept refrigerated and consumed within 24 hours to maintain its properties.

How to prepare an isotonic drink?

Simply mix water, carbohydrates (sugar, honey, maltodextrin) and a pinch of salt, possibly supplemented with fruit juice.

What is the composition of an isotonic drink?

It contains water, simple and complex carbohydrates, electrolytes (sodium, potassium, magnesium, chloride) and sometimes natural ingredients.

What is the recipe for an energizing isotonic drink for running?

For a simple recipe, mix 500 ml of water with 250 ml of fruit juice (orange or lemon). Then add 20 to 40 g of sugar or maltodextrin, and a pinch of salt to compensate for electrolyte losses.


Conclusion

Drinking an isotonic drink during a trail run helps to support endurance, compensate for water and electrolyte losses, and limit muscle fatigue.

Whether you are on a short circuit or an ultra-trail, it's important to adapt the composition, quantity, and consumption rhythm of your drink to get the most out of your effort.

By incorporating these practices, you optimize your performance while preserving your comfort and recovery.

 

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