Hydration Before, during and After the Race

We know the importance of good hydration when we practice running, both in training and in competition.

But what should you drink?

When to drink?

Drink at what quantity?

These are the questions we will try to answer here.

Hydration is an important point not to neglect in the diet of the endurance sportsman. It is used to compensate for water and electrolyte losses associated with perspiration.

It should be known that dehydration of 1% leads to a decrease in performance of 10%. Hence it is important to know a minimum and drink enough (but not too much), before and during a race and not to forget to re-hydrate properly after the event.


Hydration before a Race:

Before a competition, we drink and sufficiently hydrated. A simple way to gauge your hydration is to monitor the color of the urine. If the urine is too dark means that the state of hydration is insufficient in most of the cases.

Training is also an opportunity to measure water needs that vary from person to person. We can indeed weight ourselves before and after a session. The difference in weight then indicates the water loss generated by the effort.

If you have drunk during this race you must add the amount of water consumed to the difference in weight. It is necessary to reduce this quantity to the duration of the effort to have an idea of ​​the quantity of water to be ingested per hour.

In the theory of hydration, it is between 0.6-0.8 l per hour. It may, however, vary slightly from one individual to another. Higher water intake of this quantity is not recommended. It may lead to hyponatremia (lowering of sodium levels in the blood).

Training is also an opportunity to test the required water quantity lost during the effort and that suits you best.

The requirement of the water during the effort will be greater as the weather is cold and the test is long, but always making sure to remain isotonic. In hot weather, we recommend drinking around 20-30 g / L. In cold weather and on longer running we recommend a drink dosed at 60-80 g / L.

Read More: How to Carry Water with You Daily and Stay Hydrated

Beat the heat with coldest bottle


Waiting Drink: (Drink before the Race)

For the waiting drink, we recommend a fruit juice mix with water in a 50-50 ratio so as to limit the risk of reaction hypoglycemia, but also to preserve the glycogen stores.

Prefer an apple or grape juice or an orange juice, especially for people prone to gastroesophageal reflux.

However, sugar brought by fruit juice can give diarrhea to people with fragile intestines. It is, therefore, necessary to test this strategy at the training.

Drink during the Race:

For a race lasting more than two hours, it is advisable to drink at the beginning of the race at the rate of 25 cl / 20 min. This quantity of drink can be swallowed once or in several sips if you can’t stand the gastric weight resulting from this ingestion.

The drink will preferably be a stress drink whose concentration has been adapted to the ambient heat. It is important that the drink contains salt at 1.2 g / L (approximately one pinch), especially if the temperature is high.

During a marathon, where drinking is conditioned to refueling, it may be useful to take a small water bottle and keep it by hand to hydrate regularly, while consuming a drink from the effort to refueling, especially if it is hot.

On very long tests, in order to increase the supply of energy, add fruit juice and glucose in a ratio of 1/3 2/3. However, fruit juices can give diarrhea, it is important to test this kind of mixture in training.

You can also increase the energy intake by taking a drink containing amino acids (BCAA). This increases the energy intake by using other channels of absorption and processing, the carbohydrates can be saturated.

Read On: Drink Enough Water to Remain Hydrated


Note that on a race like a marathon, the lipid sector is very little used especially in much-trained runners.

In the effort, it may be interesting to add potassium at 300 mg / L. Vitamin B1 with the water.

You can make a homemade drink for hydration. It includes water, lemon juice (1/2 lemon for one liter of water), a pinch of salt per liter, and 30-40 g of sugar per liter (see more 60-80 g / L) depending on the heat. You can add a teaspoon of potassium gluconate per liter (buy from a pharmacy).

Do not use soft drinks during exercise because they can cause bloating and gastric and intestinal discomfort.

Re-hydration after a Race:

In the first minutes after the competition, it is important to quickly re-hydrate your body. For this, the only effective drink is water, possibly with a pinch of salt per liter to promote absorption.

An exercise drink or a solid diet would delay re-hydration. This phase lasts about 30 minutes, during this time water will be assimilated. Again, it is useless to drink a large quantity of water precipitately, which would not be absorbed anyway. A quantity of 0.4 l in half an hour drunk in small sips or twice is ample.

Read More: Hydration: Well Hydrate Yourself with 7 Things to Know



Once the sensation of thirst has passed, one can begin to ingest a drink of effort or a solid diet to replenish stocks of glycogen, and electrolytes (mineral salts).

A drink of isotonic stress will be absorbed faster than a solid diet and will continue to moisturize your body that still needs it. A drink containing bicarbonates may be good to fight acidosis.

Ingestion of fruit juice or soda should be avoided because their sugar concentration is too high. If you are a fan of these drinks, consider cutting them in equal proportions to make them isotonic and not to delay their absorption.

You should not use beer, tea, and coffee. This would cause a loss of water greater than the intake, which we obviously want to avoid in the re-hydration phase.