I only know because I started watching my health some years ago in part because of some bad blood pressure readings, but all the research I’ve done suggests that there are many causes of high blood pressure and many things you can do to lower it that work for some people.
Once I started keeping a food diary (where you record all the nutrient info for foods you eat in a day over many weeks) I realized that table salt is basically negligible in terms of the food situation here in the United States. Unless you’re specifically trying to eat a small amount of sodium I would wager you average 3,000mg a day or more and possibly 5,000mg a day or more. Pretty much all restaurant food (from QSR to casual dining) is very high in sodium, pretty much all processed food is high in sodium (unless it is advertised as low sodium, in which case it may be low), and a large portion of frozen foods are very high in sodium as well. Exceptions to that last one are plain frozen produce as they tend to have little to no sodium. Canned vegetables (unless advertised as low salt) tend to be very high in sodium as that’s part of what the manufacturer is using to preserve the food. Plain frozen veggies tend to not be high in sodium because they are just relying on temperature for preservation.
Anyway, when I looked into it some years ago it was very unclear if sodium is truly the culprit in HBP…and from what I can tell conflicting studies since then have made the picture much less clear. But yes, based on my research back then an unusually high salt intake can definitely cause raised blood pressure. But so can drinking a huge amount of water and needing to urinate really badly right before getting the reading.
For me I started doing daily cardio 30m/day (which I used to do for basically my entire life as a teenager up through age 40 and stopped for 5 years out of laziness), kept sodium intake under 2500 and lost 60 pounds. My blood pressure wasn’t high after that, so I quit watching sodium so closely and it hasn’t changed since. So for me I think the return to doing cardio and shedding excess fat got my elevated blood pressure down (I was just pre-hypertensive), and since I haven’t really paid attention to sodium intake since then and my blood pressure is still fine I don’t believe I’m one of the individuals who is especially susceptible to sodium.
FWIW I tried to follow a version of the “DASH” nutrition plan at first, which basically specializes in low sodium. Also with sodium, it appears for most people you can consume a large amount of sodium as long as you also consume a large amount of potassium, and keep hydrated appropriately. Basically if you eat a lot of sodium but don’t have high blood pressure, then sodium probably isn’t actually a big concern for you. If you lower blood pressure through other means (as I did), and notice that subsequent unrestricted sodium intake has no measurable impact on blood pressure then that’s also probably indicative you don’t need to worry about your sodium intake.