Does such salt is enough?

Am read,that on the hot weather is salted water need to drink, that she is prevents for dehydration, but does is harmful?
Such water drink on the hot water, and in strong physic loads, but on an other cases water is simple to drink on three l/day, and importance,that if you not to want, as for adults, and who is thirst absorbing is low, but is individual case are in chronic,heart failure, hypertension,where is water needing lowering, thus here in hot controlling weight by is water drinking, thus use a modern scales, as everyday check this and write in diary, as one kg loosing or more is weight dehydration, thus liquid need to rise.