Thirst
If you are feeling thirsty all of the time, you are most likely suffering from dehydration. When you become dehydrated, your body has lost a significant amount of its water volume. Thirst is part of how your body lets you know that you are low on water. If you become significantly dehydrated, your blood volume can drop, leading to a dangerous drop in blood pressure that can cause poor blood flow to your brain and other organs.
Salt Craving
If you crave salt, you are likely suffering from low sodium levels, also known as hyponatremia. Sodium is an electrolyte, which means it has an electrical charge when it is dissolved in water and blood. The levels of sodium in your blood are important for the function of all your cells, and a lack of sodium can cause confusion, fatigue, muscle weakness, appetite loss, restlessness and seizures.
Dehydration and Hyponatremia
If you find yourself constantly craving both salt and water, you may be suffering from both dehydration and hyponatremia. Some medications, such as diuretics, can deplete your body of both water and sodium by increasing your urine output, causing you to lose both sodium and water. Because your kidneys regulate your water and electrolyte balances, kidney disease can also cause you to become dehydrated and hyponatremic. Excessive sweating can also cause fluid and water loss.
Considerations
If you occasionally find yourself craving salt and water after an intense workout, you most likely do not have a serious medical problem. However, persistent thirst and craving for salt may signify that your kidneys aren't working properly or that you have a hormonal imbalance that is causing your kidneys to excrete too much water and sodium. Talk to your doctor if you have a persistent craving for salt and water.