Why sodium affects people differently
Dietary sodium can raise blood pressure by increasing fluid retention and influencing vascular tone, but the size of the effect varies between individuals. People described as salt-sensitive show a sharper rise in blood pressure when sodium intake goes up and a clearer fall when it drops. Others show a relatively flat response across a similar range of intake.
Salt sensitivity is more common with older age, certain genetic backgrounds, higher body weight, and some chronic conditions. There is no simple at-home test for it, so it is usually inferred from how blood pressure responds over time.
What the population guidance reflects
Because salt-sensitive individuals cannot be easily identified in advance and tend to be at higher risk, public health guidance generally recommends moderating sodium intake at the population level. Most major bodies suggest limits well below typical Western intakes, though exact targets differ between organizations.
This describes general patterns and population guidance, not a personal prescription. This is educational information, not medical advice; sodium targets for an individual, especially with kidney or heart conditions, should be set with a qualified clinician.