The common recommendation for heart health is 1500 mg a day or less, but honestly, I think that's kind of low. 2000-2500 is probably fine. I wouldn't worry about it too much unless you are going way over 3000 mg a day, which is very easy to do depending on what you eat. And if that's the case, just cut back on some of that stuff to get it back down around the 2000s somewhere. The link between sodium and heart problems is somewhat dubious. I'm definitely not trying to say that you should cut intake down for health reasons. This is purely to try to reduce excessive water retention while dieting.
Now too low of sodium is probably not a concern unless you are running a lot, like hours a day, and drinking tons of water too. If you are doing something like that, you'd want to get more sodium, of course. There may be some cases when dieting where you might want a little more sodium as well. I've found with keto type diets or even PSMF style, increasing sodium (as well as potassium, magnesium, etc) seems to help combat the fatigue you can feel on those diets.