During training: pay attention to your nutrition strategy.

Isotonic drinks, gels, bars, bananas, dates, guavas…

If you practice any endurance sport, you've probably already been told that you need these products to keep you upright.

But are they really indispensable?

In this article, we will analyze when and how it is necessary to use them to optimize performance.

Carbohydrates: the fuel for exercise

Carbohydrates are, without a doubt, your main source of energy during exercise, especially in high-intensity and long-duration activities.

We obtain them from foods such as cereals, fruits and tubers, and they are stored in the body in the form of glycogen in the liver and muscles.

During exercise, this glycogen is broken down into glucose, providing energy for the muscles and helping to maintain performance.

However, Glycogen reserves are limited and are depleted as activity progresses, depending on factors such as duration, exercise intensity, training level, and prior nutrition.

When glycogen stores are depleted, the body can turn to fats for energy, but this process is not as efficient in medium or high intensity exercises.

Therefore, in certain situations, It is important to consume carbohydrates during exercise to maintain energy levels and delay fatigue.

When and how much should I consume carbohydrates during exercise?

The amount of carbohydrates you should consume during exercise depends on its duration.

As time increases, the need to replenish energy also grows, as glycogen reserves decrease.

• 30-75 minutes: In short sessions of up to 75 minutes, you don't need to consume carbohydrates if you've eaten properly beforehand. With your glycogen stores full, your body should perform well during this time. Note: Mouth rinses with carbohydrates have been shown to activate neural signals that indicate to the brain that energy is available, which can improve performance without the need to ingest them and avoid gastrointestinal discomfort.
  
  
• 1-2 hours: From the first hour onwards, it becomes beneficial to consume carbohydrates, with an intake of around 30g per hour to improve performance.
  
  
• 2-3 hours: In exercises of this duration, it is recommended to increase intake to 60 g per hour to avoid fatigue and maintain an optimal energy level.
  
  
• More than 2.5 hours: In ultra-endurance activities, glycogen stores are practically depleted, so it's necessary to ingest up to 90 g of carbohydrates per hour to sustain the effort. Interestingly, it has recently been observed that some professional athletes, with highly trained gastrointestinal tracts, consume up to 120 g of carbohydrates per hour. However, this practice requires further scientific studies to confirm its efficacy and safety in other athletes.

Here you can better understand how to choose and prepare a sports drink according to the needs of the exercise.

Saturation of carbohydrate transporters

For carbohydrates to provide energy during exercise, they must be digested and absorbed through the gastrointestinal tract.

The main glucose transporter (SGLT1) can absorb up to 60 g per hour. Exceeding that amount can saturate it, hindering absorption and causing discomfort.

To ingest more than 60 g/h without problems, it is recommended to combine carbohydrates that use different transporters, such as glucose and fructose, in a proportion of 2:1 or 1:0.8 to optimize absorption and avoid gastrointestinal problems.

Below is a summary table of the points discussed previously:

(adapted from: Jeukendrup, A. (2014)

Key Points to Optimize Intra-Workout Nutrition

1. Train your gut: If you've never consumed carbohydrates during exercise, start with small amounts and gradually increase them according to how you feel. It's essential to train your gastrointestinal tract to avoid digestive problems.

2. Personalization: Nutritional needs vary depending on the sport, climate, individual tolerance, and digestive training. Seeking professional guidance will allow you to tailor your nutritional strategy to your specific needs.

3. Pre- and daily nutrition: Make sure you maintain a proper diet before training or competition, as well as in your daily life. This ensures your glycogen stores are full, which helps you perform well, recover better, and reduce the risk of injury.

4. Try out what you're going to use in competition: Never introduce anything new on competition day. Practice during your training sessions with the products you plan to use to ensure your body tolerates them well and avoid surprises.

​Jeukendrup, A. (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise." Sports Med 44 Suppl 1: 25-33, 2014.

by Alan Chamah - Sports Nutritionist