The sensation of feeling thirsty is caused by a variety of factors, but one of the main causes is dehydration. When our bodies lose fluids, such as through sweating, urination, or vomiting, we can become dehydrated. As the level of fluids in our bodies decreases, our bodies send signals to our brains to let us know that we need to replenish the fluids.

One of the main ways that our bodies send these signals is through a hormone called vasopressin, also known as antidiuretic hormone (ADH). When our bodies are dehydrated, the level of ADH in our bodies increases. This hormone helps to regulate the amount of water in our bodies by signaling to our kidneys to conserve water and reduce the amount of urine produced. As a result, we may feel thirsty as our bodies try to conserve water and maintain proper fluid balance.

In addition to the release of ADH, other factors that can contribute to feeling thirsty include an increase in body temperature, an increase in the concentration of electrolytes in our bodies, and certain medications or medical conditions.