Dehydration: When Water Isn’t Enough

by | Jul 24, 2023 | Nutrition

Image: Shutterstock

When you're sweating, it isn’t just water that leaves your body; it’s also other vital substances called minerals. But exactly what is it about minerals that makes them vital?

If your body loses too much water and becomes dehydrated, you may experience fatigue, headache and muscle weakness. In severe dehydration, the body stops sweating, and urine, if it’s produced at all, becomes dark yellow. These symptoms of dehydration, and the associated threat to your health, are not only due to the lost water. Let’s talk about why. 

The water in your body is not pure; there are many substances present in it. Some of those are substances called minerals. Literally, the word “mineral” means “something that is mined,” and that’s quite true—minerals are found in rocks and dirt. A given mineral is not a blend of substances; it is a pure material. Most rocks are composed of several minerals. Crystals, however, are composed of single minerals.

There are many types of minerals in your body; those that are present in relatively large amounts are calcium, magnesium, sodium, chloride, potassium, and phosphorus. Calcium is by far the greatest amount, making up around 2 pounds of the total weight of an adult human body. (When a body is cremated, the roughly 5 pounds of ashes consist almost entirely of minerals.) 

That’s the “what” of minerals, but what’s the “why”? For what purpose or purposes are there so many of these substances in your body? It turns out that they are essential to many vital functions. Here are three: 

  1. Differences in mineral concentration, particularly sodium, will cause water inside your body to move from one place to another, such as into and out of cells. In particular, your kidneys make use of this action to draw excess water out of your blood.
  2. In nerves, the minerals sodium and potassium provide a channel for the transmission of nerve signals, much like the wires behind an electrical outlet.
  3. In muscles, calcium plays a key role in the mechanism that causes contraction, and magnesium blocks calcium, allowing muscles to relax. In fact, it’s calcium that causes body muscles to freeze shortly after death, causing the phenomenon known as “rigor mortis,” or “the stiffness of death.”

Minerals are essential to the operation of kidneys, muscles, and nerves

So whether it is the motion of water in the body, the motion of information along your nerve channels, or the motion of your muscles, that motion is made possible by minerals. And since the water in your body has minerals dissolved in it, then when water leaves your body, whether as sweat or urine (or when there is blood loss), its takes minerals with it.

The conclusion: when you lose more minerals than you take in, such as through heavy sweating, that can inhibit your body’s ability to move water, information, and muscles, not just because you’ve lost too much water, but because you’ve also lost minerals that were in the water.

How can you be sure you’re putting enough minerals into your body, or rapidly replenish them when needed? Most minerals are found in just about all natural foods; the availability of minerals from processed and ultra-processed foods will depend on exactly what the processes were that produced the food. Minerals are also found in water, whether tap water or bottled water, with two exceptions: distilled water, and water which has been purified through the process of reverse osmosis. (The processes of distillation and reverse osmosis remove minerals.) 

There are two minerals which are not generally found in abundance in plants, because high amounts are actually toxic to most plants: sodium and chloride, which join to make what we know as table salt. Animals must get the salt they need to survive from natural water sources or deposits which can form on the ground, or from eating other animals.

If you find yourself in need of rapidly replenishing your minerals, there are commercially available drinks made for that purpose. Generally such drinks are named for certain specific minerals that are found in your body, minerals which often carry an electrical charge. Those minerals, and the drinks, are called electrolytes. A word of warning though—many such drinks contain large amounts of added sugar. Check the label. 

Also, keep this in mind: if you are dehydrated or sweating heavily, drinking an excessive amount of pure water can actually lower the concentration of available minerals in your body. It’s best to take your water along with minerals, ideally in the form of real foods, such as watermelon, citrus, dried fruits, dairy, beans, and salted nuts.

Fundamentals of Health Alliance

Fundamentals of Health Alliance


The Fundamentals of Health Alliance works to publish useful and reliable information about nutrition and health. Their mission is to empower readers to be informed with honest, non-biased information about food, nutrition and the vital components of health.

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