In mice, losing potassium and water inside their cells happens before their blood pressure goes up — and this might actually help cause the high blood pressure, even if salt isn't building up at first.

When mice eat a lot of salt, adding a moderate amount of potassium lowers their blood pressure, showing that potassium's main benefit might be fighting high blood pressure caused by salt.

When these special mice have high blood pressure, their bodies seem to react by saving water — they drink more, their kidneys change how they handle water, and blood flow to the skin drops, possibly because their cells are losing water.