One of my marathon training tactic is to drink plenty of water the day before my long runs. I call it fluid loading.
Fluid loading is like carbohydrate loading, except with water instead of carbohydrate. Carbo-loading entails gobbling carbohydrate before a long race to maximize muscle and liver glycogen stores. Fluid loading entails drinking extra fluid to achieve a “hyperhydrated” state before a race to minimize the effects of dehydration.
I use this tactic in my marathon training because during my training runs (my long runs can be up to 30 – 32Kms) I don’t carry water to rehydrate along the way. The goal is to train my body to run on minimal water.
While this tactic is advisable for training it is unnecessary before a race because at a race there will be enough water stations for re hydration. Before a race the water intake can remain at your normal levels to maintain hydration.