Why is hydration important? (10 benefits of staying hydrated)

From the desk of
Robb Wolf
ScienceWhy is hydration important? (10 benefits of staying hydrated)

Most people know that hydration is important. Unfortunately, most people also think about hydration incorrectly.

It’s not their fault. From a young age, we’re taught that more water is always better. People think that if we don’t drink eight 8-ounce glasses of water per day, we’ll shrivel up like a prune in Death Valley. But is there any science behind this 8×8 rule?

The 8×8 strategy seems to have originated with Irwin Stillman, a doctor from the 1960s who advised drinking 64 ounces of water per day. This was actually less than the 84-ounce target set by the US National Academy of Science in the 1940s. Neither target is backed by scientifically rigorous data.

This confusion around hydration has consequences. Many athletes overhydrate with plain water and exhibit symptoms of low blood sodium levels, also known as hyponatremia. Particularly in endurance sports, this condition is unfortunately common and dangerous.

“Chug more water” recommendations also create issues for people on low-carb diets, whole foods diets, and fasting regimens. These health-conscious folks tend to over-consume water while neglecting another pillar of hydration: sodium.

When people dial in their electrolytes, they feel better almost immediately: better energy, mental function, sleep, athletic performance, and more. First, let’s cover the basics.

The Right Way to View Hydration

Think of hydration as a process that requires two inputs: water and electrolytes

The truth is, healthy people rarely become dehydrated. Why? Most people get enough water already. When our bodies need more water, special receptors tell a region in our brain — the hypothalamus — that our blood volume is low. Then we get thirsty and drink something.

We don’t have such an elegant system for electrolyte intake. Yes, we do crave salty things — and this helps us consume enough sodium to get by — but as for what’s optimal, our sodium craving isn’t quite as powerful or finely tuned as thirst.

And electrolytes (sodium in particular) are essential for hydration. Let’s unpack the science behind why this is true.

What is Fluid Balance and How Does it Work?

If you look up hydration in a medical textbook, you’ll find continual references to fluid balance. Hydration is all but synonymous with this term. Fluid balance describes how water is distributed throughout your bodily tissues. And since we’re mostly water weight, this distribution matters.

Think about it. What makes your blood flow? What keeps your skin moist? How do you excrete toxins through sweat, urine, and feces? Fluids. Proper fluid balance (aka, healthy hydration) means all this machinery is running smoothly. It means that blood, sweat, tears, and pee flow properly, among other functions.

Along with water, electrolytes are key constituents in this system. Sodium regulates fluid outside your cells, while potassium regulates it inside cells. For the most part, your body does a nice job maintaining fluid balance without any conscious direction. Here’s how:

  • If you drink too much water, you excrete more fluids through urine.
  • If you don’t drink enough water, you become thirsty.
  • If you consume too many electrolytes, you excrete more electrolytes through urine.
  • If you consume too few electrolytes, your body pulls these minerals from bone.

You can pass a blood panel and still be electrolyte deficient. It’s important we get optimal amounts of both water and electrolytes to keep things running smoothly.

10 Benefits of Staying Hydrated

When you consume sufficient water and electrolytes, your bodily fluids will be nicely balanced. Here are 10 ways your body will thank you.

#1: Better energy

Low energy is a red flag for sodium deficiency. We see it all the time, especially in athletes (who lose extra sodium through sweat) and those who eat a low-carb diet or practice fasting (who lose extra sodium through urine).

Anecdotally, dialing in my electrolyte intake made me feel like a whole different animal on the jiu-jitsu mat. Many of the symptoms I’d attributed to blood sugar or other issues was, in fact, inadequate sodium intake.

#2: Improved brain function

Brain fog is another common symptom of sodium deficiency. Sodium is critical for brain function. Along with potassium, it conducts electricity between brain cells so you can read these words. Your brain also depends on proper fluid balance to stay suspended in cerebrospinal fluid. Yet another reason to drink electrolyte water.

#3: Fewer muscle cramps

Most people believe that dehydration causes muscle cramps, but the science says otherwise. Even losing 5% of one’s body weight in water (severe dehydration) doesn’t seem to increase cramp frequency. A more likely cause is electrolyte deficiency.

In the 1920s, salt supplementation reduced cramping in industrial workers, and more recently, football players with saltier sweat cramped more frequently than their teammates. Get enough sodium for proper fluid balance and you’ll cramp less. Simple as that.

#4: Fewer headaches

A headache can have many causes. Two of the potential causes are dehydration and electrolyte deficiency — so if you aren’t hydrating with water and electrolytes, headaches may follow.

#5: Better performance

When you sweat, you lose both water and sodium. Both need to be replaced to keep your body humming along. Visit the finish line of any marathon and you’ll see the consequences of replacing only H2O. A large percentage of endurance athletes need medical care, often in the form of intravenous saline. The more you sweat, the more sodium you’ll need. In warm climates, athletes can lose up to 7 grams of sodium per day!

#6: Easier fasting and keto

Both keto and fasting keep the hormone insulin low. Low insulin then signals your kidneys to excrete more fluids and electrolytes through urine. The resulting deficiencies cause a constellation of symptoms — headaches, low energy, brain fog, cramps — called keto flu. Bumping up electrolytes (especially sodium) generally fixes it.

#7: Healthy blood pressure

High blood pressure (hypertension) is a well-documented heart disease risk factor. Electrolytes are important for mitigating this risk.

Potassium in particular has been extensively studied in this area. Higher potassium intakes are correlated with lower blood pressures, and potassium supplementation has been clinically shown to decrease blood pressure in folks with hypertension.

What about sodium? Isn’t it bad for blood pressure? While people with high blood pressure may benefit from reducing their sodium intake, that doesn’t mean everyone benefits, or even that sodium causes high blood pressure. Read this article to learn more.

#8: Smoother digestion

Staying hydrated is essential at all stages of digestion. Water is the lubricant that keeps things moving along down there. Magnesium can also help with constipation. The form most studied for its laxative effect is magnesium oxide.

#9: Skin health

Skin health depends on hydration status. If you’re not hydrating properly, you may end up with dry skin or cracked lips. But dry skin doesn’t prove you’re dehydrated. This condition, like most, is multifactorial. Zinc deficiency, vitamin A deficiency, low ambient humidity, and many other factors affect skin health.

#10: Improved sleep

The main electrolyte studied for sleep is magnesium. Supplementing with magnesium has not only been shown to reduce insomnia but also to increase deep sleep in elderly people. Sodium affects sleep too. It’s been shown, for instance, that a sodium-restricted diet decreases deep sleep, REM sleep, and wakefulness overnight. Why? Probably because salt restriction stimulates the release of adrenaline, a stimulating chemical that helps you retain sodium.

How To Stay Hydrated

Your body is good at regulating water intake: Simply drink to thirst. It’s not as adept, however, at nudging you to consume electrolytes. That’s why it’s important to consciously ensure that you’re consuming enough.

How much is enough? To my eye, the literature suggests optimal intakes are between 4–6 grams of sodium, 3.5–5 grams of potassium, and 400–600 mg magnesium. Sodium, potassium, and magnesium deficiency are all fairly common — most people aren’t hitting these targets.

If you sweat often, practice fasting, eat a low-carb, paleo diet, or whole foods diet, or any combination of the above, then pay special attention to your sodium intake. Measure what you’re getting, then adjust based on how you feel — your energy, cognitive function, muscle cramps, headaches, and sleep quality all stand to benefit from avoiding sodium deficiency.

For a lot of folks, sodium is the missing link to optimal hydration. You’ll feel the difference when you get it right.

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