The issue is twofold:
Firstly, if you sweat out salty water but only replenish it with plain water, you’ll have a deficiency of electrolytes, the most abundant of which is sodium (table salt). The only way your body can correct a lack of sodium is by expelling more water. So without enough salt, you cannot retain enough water to stay hydrated. Conversely, too much salt leads to retention of water, causing high blood pressure.
Secondly, electrolytes like sodium, calcium, magnesium, and potassium are neurotransmitters. We use them for a whole bunch of things, from firing electrical signals from our brain down to our muscles through our nerves, to contracting muscles, to relaxing muscles. A deficiency can lead to muscle cramping, or more seriously an inability to control muscles and issues with the nervous system (and most seriously, cardiac arrhythmias because your heart is a muscle).
Latest Answers