# Monosaccharides in competition: galactose, D-ribose and the role of the brain

> At high intensity it is not only muscle that limits performance but the central nervous system too. What research shows about monosaccharides, galactose and central fatigue - and how WOO® Competition is built.

At high intensity the head becomes the limit before the legs do. Anyone who has felt concentration fade before the muscles gave in knows the phenomenon. Sports nutrition research has a surprisingly sugar-related explanation for it.

## High intensity places different demands on sugar

At 85 to 95 per cent of maximum heart rate, blood flow to the digestive tract drops sharply while energy demand rises. That is why many athletes tolerate less in competition than they do without trouble in training. What is needed are carbohydrates that require as little digestive work as possible and reach the cell via several routes.

Monosaccharides are the simplest case: they no longer need to be split, and different sugars use several transport routes in parallel.

## Galactose and D-ribose: two special routes

**Galactose** takes its own path via the liver, where it is fed into glucose metabolism. It is regarded as an energy carrier for the brain and thereby supports mental strength in competition. Its metabolism is less insulin-dependent than that of glucose, which contributes to a steadier blood glucose profile.

**D-ribose** is not a classic energy carrier but a building block: it is the sugar component of the ATP molecule itself. After intense efforts the nucleotide pool of the muscle cell is reduced, and rebuilding it by the body's own route takes time. **Fructose**, too, is taken up via its own transporter and metabolised primarily in the liver.

## Central fatigue: why the brain counts

Chambers, Bridge and Jones showed something remarkable in 2009: simply rinsing the mouth with a carbohydrate solution - without swallowing - improved time-trial performance and activated reward areas in the brain on fMRI. The effect also occurred with non-sweet carbohydrates, so it was not a taste effect. There are apparently receptors in the oral cavity that report energy availability to the central nervous system.

This explains why carbohydrate intake works in competition even when muscle stores are, on paper, not yet empty. Fatigue is not only a substrate problem but also a regulatory decision of the central nervous system.

## How WOO® Competition is built

**[WOO® Competition](/en/shop/woo-competition-can)** is designed as a competition drink and is based on the monosaccharides fructose, galactose and D-ribose, complemented by maltodextrin. One 80 g serving provides 80 g of carbohydrate and 313 kcal, plus 700 mg of sodium and 24.8 mg of magnesium. Magnesium contributes to normal muscle function and to the reduction of tiredness and fatigue.

The high sodium content is no accident: at high intensity and the corresponding sweat rate, sodium losses are greatest, and sodium is also involved in glucose transport in the gut. The tub contains 15 servings. According to its usage instructions, WOO® Competition is ideal before and during competition, with dosage adapted to the individual and the duration of the effort. Vegan, lactose- and gluten-free, without artificial additives.

## Frequently asked questions

**Isn't an 80 g serving too much at once?**
The serving is meant as the amount for the whole effort, not as a single gulp. It is drunk spread across the duration of the race, and concentration is controlled via the volume of water.

**Why monosaccharides instead of a classic maltodextrin drink?**
Because they need no further splitting and use several transport routes in parallel. At high intensity with reduced gut blood flow that is a practical advantage.

**When do I use Competition and when a training drink?**
Competition is intended for high-intensity efforts and races. For long, moderate sessions, drinks based on long-chain carbohydrates are the more obvious choice.

## Sources

Chambers ES, Bridge MW & Jones DA (2009), Journal of Physiology - Carbohydrate sensing in the human mouth: effects on exercise performance and brain activity.
Jeukendrup AE (2004), Nutrition - Carbohydrate intake during exercise and performance.
Gonzalez JT & Betts JA (2018), Journal of Nutrition - Dietary sugars, exercise and hepatic carbohydrate metabolism.
Coggan AR & Coyle EF (1991), Exercise and Sport Sciences Reviews - Carbohydrate ingestion during prolonged exercise: effects on metabolism and performance.

*WOO® Competition in our NEMAPO shop.*