Sodium Content and Osmolarity of Beverages vs. blood and sweat

The points here are that
1- the sodium content of beverages varies enormously;
2 - Campbell's Tomato Juice is more concentrated than blood: if you drink this, it will simply make you more thirsty.
3 - There is a broad range of potassium content in these beverages. This is not trivial, as sodium plus potassium is for several drinks very high, so that V8 juice or tomato juice will make you thirstier rather than quenching thirst or improving dehydration. Also, although for healthy people potassium protects against stroke, people with kidney disease can be poisoned by these high-potassium drinks..

Osmolality is a measure that indicates how "watery" a solution is. If the osmolality is low, it will quench thirst; if the osmolality is high -- close to or higher than the osmolality of blood, the beverage will not quench thirst.

Sport drinks are available as high-salt or low-salt drinks; only athletes who sweat hard or the unacclimated need the high-salt forms.