Will eating salty foods help with heat exhaustion?

That entirely depends on why the heat exhaustion cropped up in the first place. If the body sweats a lot, it tends to lose sodium. The sodium will need to be replaced at some point. The main problem with heat exhaustion, however, is that the body is beginning to overheat. The best treatment is to get the victim out of the heat and into a cool place. If no cool palce is available, put them in the shade and cover their body with water or some other kind of fluid to allow heat dispersal. Fanning the victim also helps.

Be sure the victim is drinking plenty of water. For better results, add a pinch of table salt to the water to replace electrolytes.