Water 

Water constitutes 55-60% of a person's body weight. Water is an important carrier in the body. It is the main constituent of the blood, urine and sweat. It serves as the solvent for minerals, vitamins, amino acids, glucose and other small molecules. It carries nutrients and waste products through the body. Water also aids in maintaining body temperature. Body temperature rises during exercise, therefore a good fluid balance is of vital importance for an athlete. Fluid losses during exercise are dependent on:

• temperature
• humidity
• duration of exercise
• intensity of exercise
• sports clothing

Drink 1,5 - 2 litres a day at rest. During exercise, it is necessary to increase liquid intake to 600-1000 ml/hour. The exact amount depends on training intensity, temperature, humidity etcetera. It is important to find out what your fluid requirements are. During extreme hot weather conditions, drink 1000-1250 ml/hour.

Note:
Avoid thirst! Thirst is a sign that the body has already lost too much water (2% of body weight). Athletes should learn to drink before they are thirsty to maintain a healthy fluid balance.

Adverse effects of dehydration