What to drink when cycling - the liquids you need on the bike

Not all liquid is created equal - we explain the different types of fluid that'll help you ride further

A male cyclist leans against a wall while drinking from a water bottle
(Image credit: Future)

Given that around two thirds of your body comprises water, knowing that you need to keep hydrated while cycling won’t be a revelation - especially when you consider that we can produce as much as two litres of sweat every hour. However, what you drink, and when, requires some thought and will differ depending on the length and the intensity of your ride.

Before we look at the different ways to hydrate on the bike, it’s worth remembering what happens if we don’t. In simple terms, the fluid loss that occurs through sweating decreases both your blood’s plasma and sodium levels, which adversely impacts your performance. 

When you’re cycling, even a small reduction in your body weight - as little as 1-2% - due to sweating will affect your muscles' ability to work. If you don’t rehydrate sufficiently the issue is only exacerbated; your blood volume reduces, your sweat rate and digestive functions slow down while your core body temperature rises and your muscles eat up your glycogen stores at a rapid rate. In extreme cases this can lead to heat exhaustion and worse but any level of dehydration will make your ride a lot less effective and enjoyable.

So what are your options for staying hydrated?


A female cyclist fills her water bottle from her kitchen tap

(Image credit: Getty Images)

What is it?

Water needs no explanation. It’s likely you’ve hydrated with good ol’ H2O for as long as you can remember. As a cyclist, it’s the most accessible, and affordable, source of fluids there is.

Why we should drink it

Drinking water throughout the day, even when you’re not cycling, is vital to your general well-being. It helps regulate your body’s temperature as well as keeping your organs functioning properly. On the bike it’s the same deal, replenishing the fluid you’ve lost through sweating and helping to stave off fatigue, headaches and a general dip in performance.

Staying hydrated in the lead up to a race or an event is equally important but be careful not to overdo it - taking on too much water before the off will only require more pit stops down the road.

When we should drink it

For rides of up to an hour plain water is sufficient on its own - any longer than this and you’ll need to supplement it with other fluids due to the effect of lost electrolytes, particularly sodium. Don’t wait until you feel thirsty, instead begin taking a few sips from your bidon as soon as you start cycling and continue to do so every ten or fifteen minutes for the entirety of the ride.

Hypotonic Drinks

What are they? 

Hypotonic sports drinks are designed to help replace fluids quickly. They are low in carbohydrates - less than 6% - and contain a lower concentration of sugar and salt than the blood, which allows them to be absorbed quickly.

A hypotonic drink is described as being of ‘low tonicity’, with tonicity being the concentration of one solution compared to another, in this case, a sports drink and your blood. They typically come in powder and tablet form which dissolve in water. Equally you could add a pinch of salt to one of your bidons and then flavour with a slice of lime.

Why we should drink them

Given that hypotonic drinks are low in carbs they’re ideal when your focus is on hydration rather than on restocking your energy sources. Unlike plain water they’ll also replace the electrolytes lost through sweating. This makes them a good match for longer endurance events where you’ll be getting your carbs from other sources or for shorter rides in warmer weather when you don’t need an intake of carbs but want to replace sodium and other important electrolytes.

When to drink them

As with water a low carb hypotonic drink should be consumed throughout the ride or race, taken in a few sips every 10 minutes or so.

Isotonic Drinks

A cyclist is drinking from a bottle while riding a bike, in the background is a field and grey sky.

(Image credit: Future)

What are they? 

Isotonic sports drinks are created to replace lost fluids while also delivering a dose of energy, so are among the best energy drinks for cyclists. They have a similar concentration of sugar and salt to the blood, which means they deliver both quickly, although not as fast as a hypertonic drink. They usually contain between 6-8% carbohydrates.

Why we should we drink them

The combination of carbs alongside electrolytes in a liquid form makes sense when you’re riding for longer periods, at a high intensity, or both. It allows you to tackle dehydration and energy replenishment at the same time, helping you to reach your hourly carb target, which will range between 30g and 120g depending on a rider’s weight and the intensity of the ride.

For shorter, high intensity rides an isotonic drink may be all you need when it comes to liquids. However for long rides it’s worth considering supplementing them with either a hypotonic drink or plain water as solely consuming isotonic drinks for extended periods can cause stomach problems, particularly if you’re also eating carb-rich energy bars and gels alongside.

When to drink them

You can drink isotonic drinks from the start of a ride to the end. However, as previously mentioned due to their higher density of carbohydrates it’s advisable to balance them with water to avoid any potential GI distress.

Hypertonic Drinks

What are they?

Hypertonic drinks are designed to maximise energy delivery. They are ‘high tonicity’, containing a higher concentration of sugar and salt than your blood with a concentration of ten or more percent carbohydrate.

Why should we drink them?

In many ways the opposite to a hypotonic drink, we should consider hypertonic drinks when energy and nutrient replenishment is our goal rather than hydration. In fact consuming them can accelerate dehydration as your body has to transfer water from your bloodstream into your intestine to help dilute them due to their high sugar content.

When to drink them

Because of their ability to dehydrate they are best used sparingly when riding - especially on long endurance rides or during hot weather. If you need a quick and efficient energy boost, then a hypertonic drink is a good choice, with a faster absorption rate than solid foods and easier to consume. However, remember not to neglect your hydration needs and use in conjunction with hypotonic or isotonic drinks. Due to their make-up, hypertonic drinks can also work well as after-ride drinks when your body craves calories, which leads us on to…

Recovery Drinks

Image shows a rider drinking a protein-packed recovery drink.

(Image credit: Future)

What are they?

The best recovery drinks contain a blend of protein, carbs, electrolytes and vitamins - all designed to ready your body ahead of your next ride or race.

Typically they’ll come in powder form to be mixed with water. Chocolate milk makes for a suitable ‘real food’ alternative or you create your own blend using protein powder mixed with an isotonic drink.

Why should you drink them? 

After a long ride or a grueling race you’ll want to replenish your body and repair it. To aid this recovery sports drinks blend carbs with proteins, often in 3:1 or 4:1 ratio. With your resting body now in an anabolic state, together they resynthesize glycogen and rebuild muscle. If you don’t adequately replenish your glycogen stores you’ll likely feel flat when you next come to train or race. Equally, without protection, you lean muscle mass will be reduced, which will likely impact your power.

When to drink them

While most recovery sports drinks will advocate being consumed within 30-45 minutes after exercise there is now evidence that our ‘anabolic window’ - the period after exercise when muscle glycogen stores are most effectively replenished - is longer than previously thought. That said, a post-ride recovery drink is likely the easiest way to begin the important rebuilding process.

Freelance writer

Luke Friend has worked as a writer, editor and copywriter for twenty five years. Across books, magazines and websites, he's covered a broad range of topics for a range of clients including Major League Baseball, the National Trust and the NHS. He has an MA in Professional Writing from Falmouth University and is a qualified bicycle mechanic. He has been a cycling enthusiast from an early age, partly due to watching the Tour de France on TV. He's a keen follower of bike racing to this day as well as a regular road and gravel rider.