# D-ribose and the ATP pool: what is really missing after hard intervals

> After high-intensity efforts the muscle cell loses part of its adenine nucleotide pool - and needs days to replace it. Where D-ribose comes in, what is established, and how WOO® Liquid Energy is set up.

ATP is not consumed in muscle the way petrol is consumed in a tank - it is turned over and continuously rebuilt. After very hard efforts, though, part of the raw material really is lost. And replacing that loss takes considerably longer than most people assume.

## Huge turnover, tiny reserve

An adult turns over roughly their own body weight in **ATP** per day. At the same time, the ATP reserve inside a muscle cell lasts only two to three seconds of maximal contraction. What enables performance is not the reserve but the speed of recharging - via creatine phosphate, glycolysis and oxidative phosphorylation in the mitochondria.

## What is actually lost during very hard efforts

In high-intensity intervals, more ADP accumulates than can be rephosphorylated immediately. Adenylate kinase produces AMP, which AMP deaminase converts into **IMP**. Part of that leaves the cell as inosine and hypoxanthine - and is gone.

The muscle cell's **adenine nucleotide pool** can drop appreciably as a result (Tullson & Terjung 1991). It is refilled through de novo synthesis and the salvage pathway, and that takes time: 24 to 72 hours depending on the load. The rate-limiting step is the supply of PRPP - a compound formed from **ribose-5-phosphate** via the pentose phosphate pathway. In skeletal muscle, that pathway runs slowly.

## D-ribose: the detour around the slow step

This is exactly where **D-ribose** comes in. As a pentose it bypasses the rate-limiting step and feeds directly into nucleotide synthesis.

Hellsten et al. (2004) tested this after intense interval training: refilling of the adenine nucleotide pool was measurably faster with ribose. Honesty requires adding that this does not automatically translate into performance - Op 't Eijnde et al. (2001) found no performance advantage in repeated maximal exercise. The mechanism is well established; the transfer to race times is not.

## Why the liquid format has its own logic

During exercise, uptake is the bottleneck: the stomach empties liquids faster than solids, and a powder has to be mixed first. A 75 ml bottle can be taken on the move in seconds.

This format combines two carbohydrate profiles: **maltodextrin** as a rapidly available energy carrier and **resistant dextrin**, which is digested more slowly. One serving delivers 25 g of carbohydrate, of which 7.3 g is sugar.

## How WOO® Liquid Energy is set up

**[WOO® Liquid Energy](/en/shop/woo-liquid-energy)** is a 75 ml drinking bottle with 1000 mg of D-ribose per serving; the pack holds ten servings. Added to that are fruit juice preparation, agave syrup, sea salt, astaxanthin-rich oleoresin (1.25 mg) and a vitamin profile.

Approved statements exist for several of the nutrients it contains: **vitamin C** (70 mg, 88% NRV) contributes to the reduction of tiredness and fatigue and helps protect cells from oxidative stress. **Niacin** (16 mg NE, 100% NRV) contributes to normal energy-yielding metabolism. **Zinc** (5 mg) contributes to the normal function of the immune system. For astaxanthin, by contrast, there are no EFSA-approved health claims.

One bottle before or during exercise. Vegan, lactose- and gluten-free.

## Frequently asked questions

**Is ribose a substitute for carbohydrate in competition?**
No. 1 g of ribose is not a relevant amount of energy - it acts as a substrate in nucleotide metabolism, not as fuel.

**When is its use most plausible?**
During repeated high-intensity efforts and in dense competition or tournament phases.

**What do the two carbohydrate sources achieve?**
Maltodextrin becomes available quickly; resistant dextrin is barely digested in the small intestine. The combination flattens the curve.

## Sources

Tullson PC & Terjung RL (1991), Exercise and Sport Sciences Reviews - Adenine nucleotide metabolism in contracting skeletal muscle.
Hellsten Y et al. (2004), American Journal of Physiology - Effect of ribose supplementation on resynthesis of adenine nucleotides after intense intermittent training in humans.
Op 't Eijnde B et al. (2001), Medicine & Science in Sports & Exercise - No effects of oral ribose supplementation on repeated maximal exercise and de novo ATP resynthesis.
Earnest CP et al. (2011), International Journal of Sports Medicine - Effect of astaxanthin on cycling time trial performance.

*WOO® Liquid Energy - in the NEMAPO shop.*