When we drink sea water, what would happen in urine formation and how is the change associate with ADH?

Question

It is often be said that when we drink 1L of sea water, we would end up excrete more than 1L of fluid.

However, the text book mentioned that as the plasma osmolality increase, which i believe it match the situation of "drinking sea water", it will end up increasing the amount of ADH and restore more water into body. it is in contraction to the common belief of losing more water.

Answer 1

Hi Chunghon L.,

Undoubtedly you will excrete saltier urine if you ingest salt in any form (i.e. ADH promotes water resorption). But, your urine output is, at most, still less dilute than seawater, so you WILL dehydrate over time ref: https://oceanservice.noaa.gov/facts/drinksw.html

Additionally, the mechanism to accomplish this requires burning proteins off from liver and muscles, so you may suffer kidney damage, cramps, and other effects from high blood pressure.

If you drank enough total water, you should be able to manage some seawater, see: https://www.nih.gov/news-events/nih-research-matters/how-body-regulates-salt-levels . Still not a great idea, check out where cholera likes to hang out!

-- Cheers, -- Mr. d.