Hydration for Cyclists

Staying adequately hydrated on the bike is as important as ensuring your calorie requirements are met by eating correctly. As with calorie/food intake your hydration should start long before you even get on the bike. Dehydration is potentially more common amongst cyclists due to the average exercise length being longer than other sports. In addition due to the high speed and wind rushing past you, evaporation can mean that a cyclist is unaware of their fluid loss until it is too late.

A good indicator of hydration levels is the colour of your urine. Ideally it should be very pale yellow/clear. A darker yellow can indicate de-hydration. This should be used as a guide only as there are a number of factors such as food consummation and medications that can affect the colour.

De-hydration can very quickly lead to a loss in performance. Not only does dehydration often give you a tired feeling but it will also reduce your energy levels. The negative effects on performance have been shown to start as early as 15 minutes into exercise if starting from a poorly hydrated state. In order to maximize your performance you'll need to ensure you are adequately hydrated before, during and after your ride.

How much fluid do you need to drink on the bike?

In normal conditions a cyclist will lose around 1 to 1.5 liters of fluid an hour through sweat however this will increase significantly as temperatures and sweating increases. Interestingly enough a large proportion of fluid loss comes not through sweating but through respiratory movement (heavy breathing), a fact proved by the fact that long distance swimmers get dehydrated.

Aim to replace your fluid be taking small drinks regularly as opposed to downing a whole bottle in one go. The main reason is that your body can only absorb the fluid at a certain rate so consuming it too quickly will only result in you being uncomfortable bloated and no having any physical benefit.

A simple way to measure how much fluid you are losing during long rides is to weigh yourself before and after a long ride. Do not forget to subtract the equivalent weight of any drinks you have consumed on the bike. Ideally you are looking for a net zero difference.

Hydration for Longer rides

For rides of under two hours only water will be required to rehydrate you. If you are attempting longer rides you may want to consider a drink with electrolytes in. Electrolytes are a mix of the minerals such as sodium or potassium that you lose through your sweat. Excessive sweating or fluid loss can result in a drop in these electrolyte level in the body which in turn can lead to a drop in performance. There are a wide variety of cycling specific electrolyte drink available in the shops. An alternative is to make your own by mixing up some diluted fruit juice, a little bit of sugar, pinch of salt and some water.

There are also a large number of sports drinks now available that contain large numbers of calories, known as carbohydrate drinks. If you struggle to eat on the bike (some peoples stomachs just can't get used to it) and out considering long endurance rides (over 2 hours) then carbohydrate drinks might be the best way for you to top up your energy stores (glycogen) on the bike. In addition the body can process these liquid fuel sources much quicker than solids, meaning the calories go from mouth to pedal much quicker.