I would think it would be hard for anybody over the age of 12 and in reasonably good health to overdose on sodium. I say that because excess sodium in the body (even a slight excess) causes thirst that is impossible to ignore. I know that because I love ham. I've often experienced the thirst that eating ham brings on for hours after eating a lot of it. As long as you have access to water and your kidneys work okay, I don't think you have much to worry about.

Diabetics know that high blood sugar damages the body slowly, whereas very low blood sugar can kill you pretty quickly. I think it is similar with sodium. Low sodium is more likely to create an immediate emergency than high sodium. That's why men working hard in a hot environment are sometimes provided with salt tablets. Sodium is lost in sweat. (Taste your own sweat and you'll confirm that.) So heavy sweating has caused laborers to collapse unconscious from loss of sodium. I've never heard of healthy adults collapsing from eating too much salty food. Putting too much salt in a baby's food could be dangerous because a baby isn't able to go get itself all the water it needs.