What causes drinking? Normally we feel thirsty when our mouths and throats are dry but this is not the whole story. Research has demonstrated the importance of kidneys and hypothalamus in maintaining thirst homeostasis. Cells in hypothalamus are sensitive not only to the relative amount of water in the blood but more particularly to cellular dehydration due to the amount of salt, which becomes concentrated as the body dehydrates from loss of water (Peck & Novin, 1971).

Prolonged water deprivation also results in the stimulation of receptors in the kidneys. Drinking more water then restores homeostasis (Simpson, 1973).

            Often we drink when we are not particularly thirsty. Kraly (1984) pointed that we typically drink during mealtime. He suggested that perhaps food causes to stimulate the thirst drive. It is also likely that we learn the habit of drinking whenever we eat or we may drink because we have heard that health experts tell us that we should drink eight glasses of water a day.