Fluid intake is important to maintain hydration when physically active and is advised before, during and after activity.The body has sensitive mechanisms to maintain hydration status and to prompt drinking but young children and older or ill adults may need support to maintain adequate hydration.
It can also be dangerous to drink excessive amounts of water as, in rare cases, water intoxication can lead to hyponatraemia (low levels of sodium in the blood).
More specific recommendations about the quantity of fluid needed at different ages have been provided by the European Food Safety Authority (EFSA) in the water dietary reference value. Current UK recommendations are to drink 6-8 glasses of fluid per day. Fluid requirements vary between people and according to age, time of year, climatic conditions, diet and levels of physical activity.Water is the most abundant constituent of the human body and regular fluid intake is essential for the body to function optimally.
