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. But unfortunately, most people also think about hydration incorrectly.

It’s not their fault. From a young age, we’re led to believe that more water is always better. People think that if we don’t drink 8, 8-ounce glasses of water per day, we’ll shrivel up like a prune in Death Valley. This 8×8 rule is widely accepted as fact, but is there any science behind it? Not at all!

8×8 seems to have originated with Irwin Stillman, a doctor from the 1960s who wrote a few popular diet books. He advised drinking 64 ounces of water per day, which was actually less than the 1940s US National Academy of Science’s target of 84-ounces. Neither target is backed by scientifically rigorous data. Some relatively recent papers have explained this better than I ever could.[*][*]

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

Beyond athletes, “chug more water” recommendations also create issues for people on low-carb diets, whole foods diets, and fasting regimens. These health-conscious folks have greater sodium needs than someone on a Standard American Diet (SAD), but they 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. I’ll cover each of these benefits in greater detail soon – first, let’s cover the basics.

The Right Way to View Hydration

Think of hydration as a process that requires two inputs:

  1. Water
  2. Electrolytes

The truth is, healthy people with healthy kidneys and sweat glands rarely become dehydratedWhy? Most people get enough water already. When our bodies need more water, special receptors in our brain tell 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. We have to rely on dietary choices for these crucial minerals. 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. Don’t just take my word for it, though—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, the electrolytes sodium and potassium 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’ll excrete more fluids through urine.
  • If you don’t drink enough water, your brain will tell you via thirst.
  • If you consume too many electrolytes, you’ll excrete more electrolytes through urine.
  • If you consume too few electrolytes, your body will pull these minerals from bone. (That’s how important they are!)

That last bullet doesn’t sound so good for bone health, does it? That’s because it’s not. An important takeaway: normal blood levels of electrolytes doesn’t equate to optimal hydration status, or optimal overall health. You can pass a blood panel and still be electrolyte deficient.

Back to fluid balance, it’s important we get optimal amounts of both water and electrolytes.

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. I 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. Fatigue is also a symptom of dehydration, but most healthy people aren’t dehydrated. Confusing one for the other is a common mistake, and it just leads to worse symptoms. That’s because if you’re already low on sodium, overconsuming water can dilute your blood sodium levels further.

#2: Improved brain function

Brain fog is another common symptom of both dehydration and sodium deficiency. And again, low sodium is the bigger problem. Sodium is critical for brain function. Along with potassium, it conducts electricity between brain cells so you can read these words (or rather, idly scan them while you daydream about your next meal). 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 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: Makes fasting and keto easier

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 bp in those with hypertension.

What about sodium? Doesn’t sodium cause high blood pressure? Actually, sodium restriction has been linked to higher blood pressures in data from the Framingham Study. And global population data has found no strong link between sodium intake and hypertension.

#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 it’s 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? 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. You simply drink when thirsty. It’s not as adept, however, at nudging you to consume electrolytes. That’s why you need to consciously ensure you’re getting enough.

How much is enough? Based on the literature, I recommend shooting for 4–6 grams of sodium, 3.5–5 grams of potassium, 400–600 mg magnesium, and 1 gram of calcium per day.[*][*][*]

Sodium is the most common deficiency. And if you sweat profusely, practice fasting, eat a low-carb, paleo diet, or whole foods diet, or any combination of the above: you may need a good deal more than that 4–6 gram baseline. Calibrate your sodium intake based on how you feel. Take into account your energy, mental function, muscle cramps, headache frequency, and sleep. Staying salty can help in all these areas.

For a lot of folks, sodium is the missing link to optimal hydration. So if you recall one thing from this chat, remember to drink electrolyte water to thirst. Hydration = water + electrolytes.

Comments are closed.