When you consider the average body is made up of 72% water, it is easy to appreciate that water has a very important role to play in feeling and looking healthy. It is estimated that there are about 45 litres of water in a 70kg man and a little less in a woman the same weight because body fat tends to be higher in women and so it displaces some of the water. It is very important to maintain a good fluid intake as low intakes can quickly lead to dehydration with many consequent side effects. Headache, light-
How much water should you drink each day?
To maintain adequate water balance, about two and a half litres of fluid should be consumed each day. About half of this should be in the form of beverages such as water, fruit juice, milk or caffeine -
Caffeine containing foods and drinks have a diuretic effect -
Water balance within the body is controlled to a very fine degree and in circumstances when intakes are low, the body responds by restricting output and the urine becomes dark in colour (more concentrated) and the volume excreted falls. Thirst is the body's mechanism that ensures you replace fluid and it usually kicks in when there is a water deficit of 200-
How can you tell if you are drinking enough?
The best indicator of your fluid status is the colour of urine. It should be a pale yellow or 'straw' colour. First thing in the morning it will be more concentrated and darker but throughout the day it should be a very light colour.
Fluid when exercising
Fluid requirements increase dramatically when exercising because the body looses water through sweating. Water is needed by the body to help it maintain it's normal temperature and so it is vital that fluid losses are made good. The amount needed will depend on;
• the length of time spent exercising
• the intensity of exercise
• the weather or environmental temperature
• your age
If it you are in a hot environment, naturally you will sweat more and lose water faster. Regular water breaks are needed in both hot and cold weather to replace body water lost in sweat, but the dehydration will set in much faster in hot weather.
Although less water will be lost during a gentle jog compared to a hard training session, nonetheless drinking before, during and after all types of exercise is recommended.
With regard to children, their body temperature increases at twice the rate of adults and so regular fluid breaks for children during exercise are vitally important.
So no matter whether you are working out in the gym, playing squash, going for a hill walk or gardening for the afternoon, keep a water bottle by your side and drink regularly.
If an exercise session lasts for more than one hour, an isotonic carbohydrate drink is recommended. This type of drink is easily absorbed and helps replenish both fluid and energy. The added carbohydrate helps protect the immune system.
You can buy isotonic sports drinks in the supermarket or you can make up your own, using either of the following mixtures:
• 200ml squash/cordial
• 800ml water
• 1g salt (pinch)
• 250ml fruit juice
• 750ml water
• 1g salt (pinch)
Fluid on a high fibre diet
When increasing the amount of fibre-
Published by VHI