For people who already have heart disease, eating just the right amount of salt — not too little and not too much — seems to be linked to the lowest chance of heart problems or dying from any cause. Too little or too much salt might actually be riskier.

If you have heart disease and eat more salt, your blood pressure tends to go up — for every extra gram of salt you excrete in urine, your top blood pressure number goes up by about 1.3 points and your bottom number by about 0.5 points.

For people who already have heart disease, having just the right balance of salt and potassium in their urine — not too much, not too little — seems to be linked to the lowest chance of heart problems or dying from any cause. Too little or too much of this balance is linked to higher risks.

People aged 30 to 54 who eat more salt over several years are 12% more likely to die from any cause for every extra 1,000 mg of salt per day—and eating very little salt doesn’t seem to help them live longer.

If you eat a lot of salt—like 18 grams a day for 10 days—your body will flush out more salt in your urine and also have a bit more salt in your blood, which proves you actually ate the salty food they gave you.

People who pee out more salt tend to have higher blood pressure, and their blood pressure tends to rise faster as they get older—but in whole populations, the average blood pressure and how many people have high blood pressure don’t seem to change based on salt levels.