I also used to say this about some joint pain I had.
I think the joint pain and the water retention are indeed getting worse these last couple of years, which either means I need to get more regular exercise, or the age thing is indeed going to make things worse and boy, howdy, that's not pretty to contemplate given where I started out.
I've done a variety of things over the last few years to try to reduce the aggregate sodium in my diet, which is tricky, because I happen to really like ketchup and low-salt ketchup is not ketchup and that stuff that Heinz makes that subs potassium whatever for some of the sodium is unspeakably weird tasting and completely intolerable. I was even making my own ketchup for a while, and I'm starting to wonder if I really should include cloves in the recipe even tho I _hate_ cloves and suspect I'm allergic to them. Which might in fact explain the mysteriously addictive qualities of ketchup for me. I mean, after the crab debacle, I'm a little suspicious of anything I have that much momentum on (but I'm not giving up chocolate. or grains. At least not without much stronger evidence of a problem).
I commented in my earlier post about turning into Crunchy Woman that I found Featherweight again, which has helped with the baked goodies. Since B. showed me it was possible to make apple crisp with oil rather than hard shortening, I've been steadily adjusting every baked goodie recipe I use to get rid of solid shortening (which is salted) and replace it with oil (which is not). I've found low sodium peanut butter. I've found no salt added Ezekiel bread. I've become quite expert in finding hamburger buns and other bread products with not-too-insanely-high sodium numbers. I've tracked down the lowest sodium beef and chicken broths on the market and usually make my own chicken broth anyway. It really does make a difference, as in, a two+ ring size difference. It's a little bizarre that this has been in no way connected to blood pressure problems (altho I suppose if I let it go for long enough it might turn into a blood pressure problem).
We've even developed a really good General Tso's Chicken, because that was one of the few things I didn't know how to cook that I regularly lusted after. Of course, even low sodium soy sauce has around 700 mg/Tbsp (altho I recently discovered Angostura has one that's 300 or so), which limits how low a dish that involves soy sauce can reasonably be expected to go.
Given how hard it has been to do this, and how even eating a couple meals outside my ordinary routine immediately affects how much water I'm carrying around (meaningfully, like, I don't wear my wedding ring), I have to say that anyone whose motivation for reducing sodium is more life-threatening than mine (like, say, someone with CHF or whatever) is basically screwed. Unless we do something collectively to require food processors, restaurants, etc. to cut back, this is going to be an increasingly difficult problem. Sure, some items have drastically reduced the amount of sodium in them (frozen peas, apparently, used to be loaded, and aren't any more. And as bad as canned chicken soup is now, it was apparently once worse). But the fraction of our diet that gets loaded up is probably higher now than it was a few decades ago (altho, to be fair, this is probably an improvement over the Bad Old Days before refrigeration).