Do athletes need extra salt

Yes, athletes perspire and eject electrolytes from their body. These essential electrolytes must be replenished, just like the body's need for water. Sodium (salt) and some other elements like potassium and magnesium are electrolytes. The ratio between water and electrolyte content in the blood needs to be in balance, or else too much water can kill you, too much sodium (salt) can kill you too.