Fuelling Your Ride: Why Carbs Matter

If sports drink advertising is to be believed, we should all be glugging litres of dayglo …

If sports drink advertising is to be believed, we should all be glugging litres of dayglo liquids. But do we really need to drink quite so much while riding? And what should we be drinking anyway? Cyclist takes a closer look at what you need and what you don’t, in partnership with Endura.

Words: Chloe McLeod and Jessica Spendlove

Drink Up

The importance of hydration and its role in performance is often underestimated by athletes, especially in the warmer months. Performance is impaired when even 2% loss of body weight is due to fluid loss. As such, implementing an individualised hydration plan is critical.

It’s important to aim to commence exercise in a well-hydrated state, particularly for endurance sports like cycling. This requires a practised hydration strategy to be implemented prior to a cycling event. The amount of fluid you require pre-exercise may vary considerably from the rest of your crew, however a general recommendation to aim for is 5-7ml fluid per kg of body mass (BM) approximately four hours pre-exercise. Following this, if urine is dark yellow, then consumption of an additional 3-5ml fluid per kg BM in the final two hours pre-exercise is recommended. If a large volume of fluid is consumed immediately before an event starts, you may experience discomfort, though 300-400ml fluid is tolerated by most without any issues.

During an event, your fluid consumption should ideally be at a rate that’s both practical and comfortable in order to replace sufficient fluid lost through sweat and avoid serious levels of dehydration. Drinking fluid during exercise will also help maintain normal muscle function and reduce the risk of heat stress. Aim to consume enough fluid to limit weight loss to <2% BM. Work this out by multiplying your weight by 2%. So if you weigh 75kg, and more than 1.5kg fluid is lost, this indicates more fluid needs to be consumed during your ride. However, it’s important to avoid overhydration. Like dehydration, overhydration has serious health risks.


Start drinking early on, and continue to sip your chosen drink regularly to maintain fluid volume and increase fluid availability. Each individual has a different tolerance for fluid volume, rate of gastric emptying and sweat loss. This is one of the reasons it’s so important to follow a hydration plan in your next race that has been practised in training. Many athletes find out the hard way why it’s never a good idea to trial a new food/hydration strategy on the day of an event!


Just the Tonic

Hit the spot with the right drop


For those looking to separate their hydration and fuelling requirements, Endura Low Carb Fuel provides just 1.3g of carbohydrate per serve while ensuring hydration requirements are met with the full spectrum of electrolytes. It also provides a tastier way to stay hydrated throughout the season.


Endura Rehydration Performance Fuel combines key electrolytes (sodium, potassium, Meta Mag magnesium and calcium) with 20g of carbohydrate to effectively replace what’s lost during endurance exercise. Sodium plays an important role in the absorption of glucose and fructose.


Stacked with a powerful 6:1 carbohydrate to protein ratio, Endura Optimizer can be used before, during and after training and racing. Easy to digest whey protein combines with branched chain glucose and fructose to provide a more steady and balanced metabolic rate ideal for athletes of all abilities. Use when fuel demands are high.


Weighing in pre and post-exercise is the easiest way to check your sweat rate. Aim to replace fluid losses by 125-150% within 2-6 hours post-exercise. One key issue with restoring hydration post-exercise is achieving a balance between fluid intake and urine losses. The addition of sodium can help with retention of ingested fluid (i.e. minimising urine losses). Sweat doesn’t just contain water; there’s also the loss of electrolytes via sweat, primarily sodium. This is why most sports drinks have this added. Sodium lost through sweat may only be minor during short events, but for prolonged rides a large sodium loss can occur. There’s considerable variation in the sodium sweat content. Those who experience high sodium (i.e. ‘salty sweaters’) must take particular care to replace sodium loss. For optimal rehydration, include sodium in post-exercise fluid.

Start early and continue to sip regularly to maintain fluid volume

Like sodium, the addition of potassium to rehydration fluid is effective in enhancing fluid retention post-exercise. Potassium may also assist in muscle contraction during exercise.

Replacement of magnesium lost through sweat isn’t required by all, as it’s often minor amounts. However, magnesium sweat concentrations can vary considerably; magnesium can be a difficult mineral to get adequate amounts of in the diet. It’s also depleted by everyday factors such as stress, alcohol and caffeine, so for some cyclists replacement may be important. While the most common form of magnesium supplementation is in tablet form, Meta Mag from Endura is found within a number its products.

Magnesium is a key element in energy production and may also assist in the management of muscle cramps if individuals are deficient or have higher requirements. Using a rehydration drink that covers off the aforementioned electrolytes, such as Endura’s Rehydration Low Carb Fuel, means you’ll have your bases covered, particularly when sweat rates are higher during these warmer months.

It’s a good idea for cyclists to undergo sweat testing to determine their electrolyte sweat content, particularly for sodium. This will assist in achieving correct fluid and electrolyte restoration post-exercise by determining the quantity of electrolytes that need to be replaced.


Top tips

Four tips for one-bike hydration management


Hydrate before, during and after the ride. If you’re going to be riding for over two hours, make sure there are some carbs in your drink. This is the point at which you’ll need to supplement your glycogen stores.


You don’t just lose water through sweat – respiratory fluid losses via the lungs can make up to 60% of overall losses. Stick to your hydration plan even when it’s inclement. Just because it’s cold or raining doesn’t mean you need less fluids. In fact, you can get even more dehydrated in winter than in summer.


Find a sports drink you like the taste of, as you’re going to be drinking a lot of it. Don’t assume that because they contain carbs and electrolytes you don’t need to drink as much. If you find sports drinks too sweet to drink continously, take an extra bottle of plain water and alternate.


The risk of overhydration is very real, especially on longer rides. Any longer than three hours and you’ll need some electrolytes to lower the risk of hyponatremia. For five hours or more it’s essential to have a fluid replacement plan to stick to. In extreme heat you can also add a pinch of salt to each water bottle.


It’s critical that athletes select appropriate sports drinks to optimise hydration pre, during and post-exercise. What to look for in a sports drink will vary depending on the type, duration and intensity of exercise. It will also depend on the specific goals and requirements of the individual. The inclusion of carbohydrate in a sports drink is important if the event lasts more than 90 minutes to help meet fluid and carbohydrate requirements simultaneously. Concentration of the sports drink will vary depending on event duration and temperature.

The sodium content should be between 230-690mg, and those with a high sodium-sweat content may require additional sodium supplementation. Most sports drinks will also include potassium, which is appropriate, and some will include calcium and magnesium as small amounts are lost through sweat.

In terms of osmolarity, most sports drinks are isotonic, which is an appropriate choice. If rapid rehydration is required, then a hypotonic variety will be more effective. Palatability and taste are also critical, as fluid intake will be higher when a drink is palatable and pleasant. Powdered electrolyte options can provide more flexibility here compared to a bottled sports drink, as you can vary the tonicity and flavour concentration simply by adjusting the amount you put in or the volume of water with which you mix it. Trial different flavours to find the one you find most enjoyable.

It’s recommended to avoid sports drinks with a very high carbohydrate content as this can cause gastrointestinal upsets and contribute to dehydration. For those who are caffeine sensitive, avoiding sports drinks with added caffeine is also recommended. Finally, it’s important to choose quality and trusted products for hydration, so a low-carbohydrate rehydration beverage like Rehydration Low Carb Fuel by Endura is an excellent choice.

Chloe and Jessica are Advanced Sports Dietitians and owners of Health & Performance Collective.