If you have pre-hypertension, having more sodium than potassium in your urine might mean you’re more likely to die from any cause — even if you’re not eating a ton of salt. It’s not just how much salt you eat, but the balance between salt and potassium that might matter more for living longer.

For older adults who are overweight but don’t have heart disease or high blood pressure, eating more salt than potassium might raise their chance of dying within 5 years by about 19%—so it’s not just how much salt or potassium you eat, but how they balance each other.

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.

For people with slightly high blood pressure, eating more salt seems to raise the risk of dying earlier—even at very low salt levels below what’s usually considered healthy. There’s no sign that eating very little salt is safe or helpful.

When people pee out more salt than potassium, their blood pressure tends to be higher — it’s like the balance between salt and potassium in your urine tells you something about your blood pressure.