Along with oxygen, water is one of the 2 most essential materials for human life. The average person can survive for about 40 days without food, but most people will die if they go for more than 72 hours without a drink.
About 60 per cent of the human body consists of water. This means that the average adult male body contains 40 litres. Water is necessary for all the chemical reactions that occur in our bodies. It lubricates our joints and is responsible for cleansing our bodies, eliminating potentially poisonous waste products.
The digestive system uses about 12 litres of water every day to process the food we eat. Three-quarters of the human brain consists of water.
For the body to keep functioning normally it needs a steady supply of water. Even without exercising we lose up to 2 to 3 litres a day through breathing, perspiration, urinary and bowel functions, depending on environmental conditions. With exercise and hot weather, this loss can increase much further.
If you exercise regularly you should drink a glass of water before starting and then have half a glass every 15 minutes. This will prevent dehydration and improve performance. A simple rule for good health is to drink 8 to 10 glasses of water every day.
Last Reviewed: 21 September 2009
You are under optimum weight for your height. Being underweight can carry health risks for both men and women. Check with your doctor or dietitian to find out if your current weight is healthy for you.
You have a healthy weight for your height.
You are over optimum weight for your height. You may be facing health problems, so losing some weight would be a good idea.
You are over optimum weight for your height. You may be facing health risks, so see your doctor to help you achieve a healthier weight.