If salt keeps water in the body, why do salt tablets make dehydration worse?

Hello, Can you please explain on your site when it says “Do not take salt tablets. Salt tablets make dehydration worse because they drain the water from your body.” I thought salt kept water in your body? Helping grandkids make a booklet on swimming and heat exhaustion, they have a VRBO house in Phoenix and last weekend it was 118. I told them they need to drink even when they are swimming. And an adult asked about salt tablets… Thanks!

Submitted by Karen from Seattle, Washington on 06/10/2016

The only good thing sbout salt tablets is that they are very poorly absorbed. This limits the damage they can do.

The definition of dehydration is the condition that results from the net loss of WATER. The concentration of sodium in our body fluids is closely regulated by the kidneys. In most cases, water is lost via perspiration and breathing. This fluid is HYPOTONIC meaning that the concentration of sodium in it is low compared to body fluids. To correct or prevent it, all that is needed is to take in more water. The small amount of sodium loss is easily replaced from a normal diet.

In hot, dry climates like Arizona, the normal kidney will adjust and water is all that is needed. When we become dehydrated, the sodium concentration in the body is already elevated. Adding salt (sodium) only aggravates the condition by forcing the kidneys to excrete more water in order to eliminate the extra salt.

In circumstances such as EXTREME exertion in hot and dry weather, severe vomiting, and diarrhea, and illnesses like cholera, special electrolyte solutions (not just sodium) are required and may need to be given intravenously. The average athlete with normal kidneys needs water. Supplements such as GatorAde can be used in situations during and following strenuous workouts, but should be in addition to, not in place of plain water. I recommend drinking 12 oz. of water before the workout and supplementing it every 45 min. during the run/ workout. The sensation of thirst indicates the onset of dehydration. If the athlete can pass urine immediately following his workout, he has kept himself well hydrated. All athletes should understand this.