Hydration is an important factor in ensuring that you/your child trains well. To ensure that all swimmers are sufficiently prepared to train, it is vital that they drink well prior and after training. They must also come prepared with plenty to drink at all sessions. A minimum requirement is 250 ml for every 15 minutes of training, water or weak squash is recommended, (1 hour - 1 litre, 90 minutes - 1.5 litres, 2 hours - 2 litres). Dehydration of approximately between 2-5% of body weight can lead to overall loss in 20-45% in performance, dependent on the type of swimmer and race/session being performed (30-45% loss in performance has been recorded in sprint athletes). Even if a swimmer has a small mass they still need to continue rehydrating after completion of training and should stick to the above rules, its sets the habits for the future.
It will take time for swimmers to understand how much is too much for hydration. Simply put, if your drinking too much you will be going to the toilet too much. If hydrating correctly, you should not need to go to the toilet until the end of the session or at least after an hour, based on the assumption swimmers go before coming poolside. Most swimmers find it funny but the simplest way to tell how dehydrated you are is looking at your urine. The attached "pee chart" will help. Previous documents on nutrition will also have this included, along with more detailed information on the signs and effects of dehydration. Thirst means you are already dehydrated.
Hydration starts 30 minutes before training and should continue after training.
Should you/your swimmer arrive for training without enough fluids to sustain themselves for the full training session, then you/they will not be allowed to swim. This is for the swimmers own good, please ensure you/they have adequate and appropriate fluid at all training sessions.
Sip every time you stop! If during training you are stopping less frequently, then drink more but never to the point it is sloshing around in your stomach as your body will not absorb it and you will end up needing to visit the toilet during the training session.