As a subject matter expert in physiology and environmental science, I can explain why drinking salt water can lead to dehydration.

When you drink salt water, which has a higher salt concentration than your body's cells, your body attempts to maintain its internal balance by drawing water out of the cells to dilute the excess salt. This process is known as osmosis. As water moves out of your cells and into the bloodstream to balance the salt concentration, it can lead to a decrease in the water content within your cells. Additionally, the high salt content can cause your kidneys to work harder to filter out the excess salt, which also requires more water. This increased demand for water to process the salt can lead to dehydration if you're not consuming enough fresh water to compensate.

Moreover, when your body senses that there is too much salt, it triggers thirst mechanisms to encourage you to drink more water. However, if you only have access to salt water, drinking more of it will only increase the salt concentration in your body, further exacerbating the dehydration.

In summary, drinking salt water can lead to dehydration because it causes your body to lose water in an attempt to dilute the excess salt and because the increased salt load requires more water to be processed by your kidneys.

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Human kidneys can only make urine that is less salty than salt water. Therefore, to get rid of all the excess salt taken in by drinking seawater, you have to urinate more water than you drank. Eventually, you die of dehydration even as you become thirstier.read more >>