Trail running preparation: nutrition and hydration, a key to success

In trail running, nutrition is crucial, especially for longer efforts.
Its importance is often underestimated: digestive problems are, in fact, one of the leading causes of dropouts in trail races.
Depending on the duration of the effort, a balance must be found before and during the race to ensure proper nutrition, maintain hydration and energy levels, and preserve digestive health.
This is a challenge that definitely warrants thorough preparation and careful management during the race!

But first, why do digestive problems occur during a trail run?

Quite simply, because prolonged exertion disrupts digestive function: the body redirects blood to the muscles to provide them with maximum oxygen, so the blood flow that normally nourishes the digestive system is significantly reduced. This , combined with stress and the impact of running, leads to stomach pain, and even nausea and vomiting.
It's such a shame to spoil the enjoyment of a race, especially one you've prepared for physically, because of stomach problems!

Eat well in the week leading up to the race

Increase your glycogen stores , the primary fuel for muscles, by following a diet rich in starchy foods (pasta, rice, bread, etc.) starting three days before the event (D-3). Experienced runners precede this carbohydrate loading with a period of glycogen depletion (D-6 to D-3) through prolonged exercise. This "boosts" glycogen replenishment through supercompensation, potentially increasing glycogen storage capacity fivefold.

Avoid allergens , at least during the week before the race: lactose (milk and derivatives), gluten (wheat, rye, oats, barley…).

Proper hydration is key during a race...

Trail running drinks contain mineral salts, but also carbohydrates and glutamine to protect the intestinal and immune systems that are disrupted during exercise.

At a minimum, you should drink 500ml of energy drink per hour, at a rate of 2 to 3 sips every 10 minutes .

The aim is to compensate for the loss of water and minerals, particularly sodium, caused by sweating, while preserving digestive comfort.

...And good nutrition

Energy gels are essential and sufficient for short trail runs (2-3 hours): highly digestible, concentrated in energy substances (short carbohydrates and maltodextrin, minerals, vitamins) and easy to use.

The consensus is to consume 1 to 2 short-distance gels per hour (20 to 40g of carbohydrates) for a 2-hour run. Beyond that, this increases to 3 gels per hour, also incorporating antioxidants (Vitamins C and E, zinc) and amino acids to combat muscle fiber fatigue.

Be careful not to overconsume them: excess carbohydrates cause intestinal fermentation leading to bloating, digestive discomfort and accelerated transit.

Energy bars (one every three hours) are a useful supplement, providing additional nutrients, a different flavor, and a satisfying chewing sensation. Consume them while walking rather than running, followed by a sip of water or an energy drink within 15-20 minutes to aid digestion.

At aid stations on long trail runs, real food is recommended for both its physiological and psychological benefits: this is "organoleptic nutrition".
Sweet: banana, compote, almond paste, walnuts and hazelnuts, biscuits, gingerbread... Savory: rice balls, sweet potato, hazelnut puree, soups to dilute, or even dried meat.

Don't hesitate to stay at Chalet La Source to prepare for or practice your trail runs. And happy running to all!