WHY STAYING HYDRATED DURING EXERCISE IS IMPORTANT
During exercise our body temperature rises. This causes our body to sweat. Sweating is the most effective way for our body to cool. If sweat losses are not replaced by consuming suitable fluids, dehydration can occur.
Your body works best when it is fully hydrated. A loss of 2% of body weight as a result of dehydration (which in an average female is as little as 1.2 kg) can cause your heart to work harder and your muscle to fatigue. In other words you don’t feel at your best and exercise becomes harder.
HOW TO OPTIMISE HYDRATION
Aim to drink 5-10ml of fluid per kilogram of your body weight in the 4 hours before training or competition. This will allow enough time for the fluid to be absorbed. For a 60kg runner, this equates to 300-600ml of fluid, or 1-2 glasses.
Our sensation of thirst is less sensitive during exercise, meaning you may already be dehydrated by the time you feel thirsty. Drinking little and often from the start is a smart way to stay hydrated but also prevent stomach discomfort and sudden requirements to use the toilet during training and the race!
For effective post-exercise rehydration, you should aim to consume 150% of the fluid lost as sweat.
So, bearing in mind that 1L of water weighs 1kg, if an athlete weighs 1kg less after exercise, they need to drink 1.5L of fluid (about 6 glasses) afterwards to fully rehydrate. Sip little and often over the following hours to achieve this.
Author - Lucozade