Hydration

Why is drinking water so important anyway?

Water is essential for life and although humans can survive for a number of weeks without food, they cannot go without fluids for more than two to three days.

Water is essential for our bodies to work properly. Water is the major component of body fluid and has many functions in the body:

• It acts as a lubricant for joints and eyes
• It is the main component of saliva, which helps us swallow
• It provides the medium in which most reactions in the body occur
• It acts as a cushion for the nervous system and helps get rid of waste
• It helps regulate body temperature.

On average, water makes up 60% of body weight (range 45-75%) and is essential for the correct functioning of all the cells in the body.

The body cannot produce enough water to meet all of its needs, so most of the water we need must be provided by our food and drink. If we do not consume enough water, we become dehydrated.

How much water do we need? The amount of water and other fluids that we need to drink each day varies from person to person, depending on age, time of year, climatic conditions, diet and the amount of physical activity we do. Water requirements are particularly increased in hot climates and when physically active.

Dehydration can be very serious; a loss of 15-20% of body weight as water is fatal, and a loss of as little as 2% (equivalent to an overall loss of about 1.4L water in a 70kg man) can result in impaired cognitive, physiological and performance responses. Symptoms of dehydration include headache and fatigue.However, drinking too much can also be dangerous as it can lead to water intoxication with potentially life threatening hyponatraemia (caused when the concentration of sodium in the blood gets too low).

It has been estimated that roughly 20% of water consumed is from food, and the remaining 80% from beverages.

We can get our fluid requirements from a number of sources as water is contained in most foods and all drinks consumed. It is not necessary to drink only ‘pure’ water, although this is a good choice.

Other drinks such as freshly made fruit juice, plant milks, tea and coffee contribute to our daily requirements too. In addition to their contribution to our water needs, what we drink may also have a wider effect on our health. Some contain nutrients and other substances that are beneficial for health.

However, it is important to be aware of the sugar and overall energy content of some drinks. Your intake of soda, squash, energy drinks and alcoholic drinks should be limited, if consumed at all.