This blog will be published in two parts. Water is essential for life. It is important we get the right amount of fluid to be healthy. However, there are lots of mixed messages about how much, and what to drink and this can be confusing.
Why do you need water?
We need water to help regulate temperature, transport nutrients and compounds in the blood, remove waste products and act as a lubricant and shock absorber in our joints.
Water is lost in urine and in sweat and is also being lost throughout the day. To avoid dehydration, you need to replace this fluid regularly with fluids from food and drinks. ‘Fluid’ includes not only water from the tap or in a bottle, but also other drinks that provide water such as tea, coffee, milk, fruit juices and soft drinks. We also take water from the food we eat.
What happens when you get dehydrated?
If you don’t consume enough fluids, over time the body becomes dehydrated. Studies have shown that at about 1% dehydration (equivalent of 1% of body weight water loss) there are negative effects on mental and physical function, and these become more severe as the dehydration gets worse. Symptoms of mild dehydration include a dry mouth, headaches and poor concentration.
When the body detects that more water is needed the first thing that happens is that the kidneys reduce the amount of water lost in the urine. This means that the colour of the urine becomes darker and you can use the colour of your urine to tell if you are well hydrated – urine should be a pale yellow colour. If it’s darker, then you need more fluid. Thirst kicks in when the body is already a little dehydrated, so it is important to drink when you’re thirsty.
How much do you need?
The amount of fluid you need depends on many things including the weather, how much physical activity we do and our age. It is generally accepted that we should drink between 6-8 glasses of fluid per day. If the weather is hot or you are exercising, you may need to drink more fluid.
Do some people need more water than others?
Needs vary from one person to the next, but there are certain groups who may need to pay particular attention to hydration. Children need plenty of fluid, despite their smaller body size, and they should be encouraged to drink regularly, especially if they are very active. Older adults may have a weaker sense of thirst and, if necessary, should be helped and encouraged to drink regularly.
Do you need sports drinks when exercising?
Physical activity also increases the amount of fluid you need to consume in order to replace the water you lose as sweat and the amount lost depends on how long you are active, how intense the activity is and the weather. It’s a good idea to start any physical activity well hydrated and to drink at intervals during activity.
Water is fine for re-hydrating after the kind of moderate exercise that most active people choose, and the majority of active people do not need special sports drinks to stay hydrated. However, for high intensity exercise that lasts more than 1 hour, drinks that contain some sugars and salt, such as sports drinks may be better at replacing the extra fluid lost as sweat.