The sweat test
How do you know how much to drink? There’s a simple to help you determine approximately how much you should consume each hour; it’s called a 60-minute sweat test. After ensuring you’ve hydrated well the previous day, regularly sipping water or similar throughout, weigh yourself nude. Then get on your bike (once you’ve dressed!) and ride at racing intensity for 60 minutes. Head back into your house, strip back off, wipe away excess sweat with a towel and weigh yourself again.
The difference in weights in grammes equates to fluid losses in millimeters. For instance, if you’re an 80kg rider and you return from your ride at 79.5kg, so losing 500g, aim for 500ml of fluid intake per hour. Whatever the figure, if you struggle to replace the entire quantity, at least aim for 75%.
Urine color is also a good indicator, with urine charts printable off the internet. However, just be aware that sometimes it’s not as simple as saying your urine’s a certain color so you’re dehydrated. Take B vitamins, for example, they’re heavily pigmented so their strong color can give the riders’ urine an orange hue. It’s also sometimes difficult to distinguish between dehydration and beetroot juice!
What to drink
Most experts agree that if riding for under 60 minutes, drinking water alone is fine. Beyond that and you’ll want to supplement with carbohydrates and electrolytes. One of the most vital electrolytes that needs replacing is sodium, which helps to maintain blood plasma volume and transport water from the bloodstream to working muscles. If the rider’s drinks contained water with hardly any sodium, the body wouldn’t retain it and it’d just be leached out into their chamois pad.
Sweat contains sodium so the more you sweat, the more sodium you lose. There are now a plethora of electrolyte tablets available to the rider, each with varying amounts of sodium. To determine exactly how much sodium you need, there are more detailed sweat tests that you can take at a lab. Or you can take another parochial test – namely, if you finish a ride and your face is caked in salt, you’re probably a heavy sodium sweater! So take one 500ml bottle and fill it with an electrolyte drink.
Carbs are king
Your other bottle should be a carbohydrate drink. Again, this is a competitive market so there are plenty to choose from. But don’t forget the key aspect: not to be blinded by science – taste is vital. It could proclaim to be the most performance-enhancing drink around but if it tastes and smells like a musty old flannel, you won’t swallow a drop. Most sports drinks are packed with a blend of simple sugars for fast energy delivery. These include glucose, maltodextrin, fructose and sucrose.
Whichever one suits, and depending on riding intensity, aim for 0.5-1g of carbohydrate per kilogramme bodyweight per hour. So returning to our 80kg rider, that’s between 40g-80g of carbs an hour. That said, like your muscles, lungs and heart, your gut needs training to digest on the move. The fitter you are, the more carbs you can ingest so a wise plan is to start at that low end and work up. You don’t want a nasty case of gastro distress to upset your ride.
As an example, 500ml of sports drink powder mixed at 7% solution will give you around 35-40g of carbs. Take regular sips rather than one huge gulp, or set a reminder on your watch to sip every 20 minutes, aiming to clear one bottle each hour.
If it’s a race, you’ll be able to top up at a feed zone, and for every other ride, equip yourself with the best hydration system possible, such as the triathlon-orientated Vision DS1.
Vision’s new DS1 drink system uses conventional water body and a CFD-designed head unit gives an aerodynamic front profile
Right, now with dehydration banished, it’s time to go and set a new PB!