It is recommended that you bring a water bottle with you whenever you exercise and drink adequate amount of water. A good guide to know when and how much you should drink is to follow your thirst. Another way is to pay attention to the colour of urine. Normally, it should be light yellow but once it turns dark yellow like chrysanthemum tea, you should drink up. A totally clear urine is overdoing it.
When drinking water, it is best not to drink too much at once. One should drink small quantities over the period of exercise. This is because our body responses through hormones have a certain lag time. When large amount of water is consumed at once, the osmotic pressure in the blood increases and the brain starts to produce less Anti-Diuretic Hormone (ADH) which decreases the reabsorption rate of water. Even when the osmotic pressure reaches the normal level, there is still an absence of the required amount of ADH to increase reabsorption. This may again cause excessive loss of water and leads to a secondary dehydration.
