“Have you had enough to drink?” You’ve almost certainly heard this question in connection with heat, sport or headaches. However, some people find it difficult to drink the recommended daily amount, which varies between one and two litres depending on your height and weight. Since we also get some liquid from the food we eat, it’s important not to confuse the recommended daily amount of liquid that you should drink with the total fluid intake. The Swiss Nutrition Association recommends a total fluid intake (from drinks and food) of two to two-and-a-half litres per day.
The human body is about 60% water. In fact, the figure for new-born babies is about 75%. The fluids in the body perform a number of functions, acting as an important solvent and medium for transporting nutrients, enzymes and hormones. Water ensures that we are able to excrete waste products, controls body temperature, and keeps the body's tissues and skin supplied with moisture. It is also essential for many biochemical reactions and regulates the metabolism of cells. Last but not least, water plays a key role in the intestine, facilitating digestion by making the stool softer.
Headaches are probably the best-known symptom of dehydration. Dehydration initially makes itself felt in the form of thirst, discomfort, loss of appetite, nausea, restlessness or increased heart rate. Other symptoms include reduced mental capability (i.e. a lack of concentration and slower reactions) and a fall-off in physical performance. Long-term persistent underhydration can also lead to an increased risk of constipation, while severe prolonged underhydration can have very serious consequences and will ultimately result in death.
“You can never drink too much!” Maybe you’ve also heard this at some time or other? As a matter of fact, it’s incorrect. Studies have shown that the brain will try to prevent us swallowing if we intend to have a drink when we are not thirsty. When we drink too much, salt levels in the body fall and there is a risk of kidney failure. If you take a lot of exercise, you should therefore stick to special sports drinks which contain salts and help maintain a healthy balance. Overhydration can lead to headaches, cramps, dizziness, vomiting or even cerebral oedema (excess water in the brain). The Swiss Nutrition Association recommends that you should only drink when you feel thirsty. The exceptions here are elderly people, children and some chronically ill individuals because they may not feel thirsty even though they actually do need more fluids. These groups should plan to drink at regular intervals.