What electrolytes do for you: Sodium-potassium pumps and fluid balance

What do neurons firing, the heart pumping, your blood circulating, and a bicep flexing have in common?

They all depend on a short list of charged minerals. Without these minerals, the perpetual flow of biochemistry inside your body couldn’t dance. It wouldn’t even know how to dance.

You can probably guess which minerals I’m talking about. I’m talking about electrolytes.

Most people think of electrolytes as hydration support. And that’s not wrong. To feel and perform your best, it’s crucial to consume electrolytes along with fluids.

Yet hydration is just a sliver of the electrolyte story. It gets a lot of attention because you REALLY notice when your energy tanks, your muscles cramp, or your brain fogs up due to improper hydration tactics—like drinking too much water or neglecting sodium.

But quietly, imperceptibly, even when you feel nothing, electrolytes are supporting the processes that keep you alive. They’re getting water in your body to the right places and allowing electrochemical signals to be sent between cells. They’re sustaining life.

I’ll dig into fluid balance, sodium-potassium pumps, and the many physiological systems reliant on electrolytes in a second. First, though, we need to cover some definitions.

What Are Electrolytes?

Electrolytes are minerals that conduct electricity when dissolved in a solvent. That solvent (in the human body and elsewhere) is usually water.

The main electrolytes are sodium, chloride, potassium, magnesium, calcium, phosphate, and bicarbonate. Of these seven minerals, only three—sodium, chloride, and potassium—are essential minerals that function primarily as electrolytes.

Magnesium, calcium, and phosphate mainly serve other functions (like building bone and repairing DNA). Bicarbonate isn’t “essential” because you produce your own supply. And since chloride always appears alongside sodium as salt, I won’t spend much time on that electrolyte either.

That leaves sodium and potassium: the heavy hitters of the electrolyte squad.

Intravenous routes aside, the only way to get sodium and potassium into your body is through diet and supplementation. That means consuming salt for sodium and potassium-rich foods (like dark leafy greens) for potassium.

You must consume electrolytes because you’re constantly losing them through sweat, urine, feces, and (on a bad day) vomit. What’s lost must be replaced. If it’s not sufficiently replaced, a variety of health markers will suffer.

The heavy hitters—sodium and potassium—have two primary roles in the human body:

  1. Regulating fluid balance
  2. Enabling cellular communication (nerve transmission, cellular signaling, etc.)

Let’s cover these individually.

Electrolytes and Fluid Balance

When I talk about optimal hydration, I’m talking about optimal fluid balance. Having the right balance of fluids and electrolytes in your tissues keeps your blood flowing properly, your brain suspended in your skull, your skin moist, your heart chugging, and much more.

Fluid balance is mostly an unconscious process. If body water gets too low, your body secretes antidiuretic hormone (ADH) to retain what fluids are left, and then you stop urinating. And if body water gets too high, your body shuts down ADH and you start visiting the bathroom every thirty minutes with a bladder full of colorless urine.

Sodium and potassium are integral parts of this system. Sodium, for instance, is the primary mineral that regulates fluids outside of cells (crucial for maintaining blood volume), while potassium regulates fluids inside of cells.

But while fluid balance is largely unconscious, three adjustable factors influence this system:

  1. How much water you drink
  2. How much electrolytes you consume
  3. How much water and electrolytes you lose through sweat, urine, feces, etc.

Ideally, factors 1 and 2 should sum to equal factor 3. Then you have a perfectly balanced system.

Factor 1 is the easy one. You have a built-in system for regulating fluid intake: thirst.

Just drink to thirst and you’ll get enough water. Drink beyond thirst (as many athletes do) and you run the risk of diluting blood sodium levels and paying for it.

For factor 2, your ideal electrolyte intake will depend on how much you lose through diet and lifestyle factors. Start with 5 grams of sodium and 4.7 grams of potassium per day as a baseline, and go up from there if you’re a heavy sweater, keto dieter, or both.

This lesson on fluid balance, however, doesn’t cover everything you need to know about electrolytes. For that, we have to talk pumps.

The Sodium-Potassium Pump

Every cell in your body requires energy in the form of ATP. But what do they need that ATP for?

In large part, cells need ATP to pump sodium and potassium ions through the cell membrane. This action, which enables everything from muscle contraction to neuronal firing, is controlled by an omnipresent enzyme system called the sodium-potassium pump.

The sodium-potassium pump wears many hats. It maintains the cell’s membrane potential (keeping the cell “charged up” for nerve impulses to fire), regulates brain cell activity, helps transport glucose and amino acids into cells, and even keeps fluids balanced within cells.

Nerve cells are especially heavy users of the sodium-potassium pump. A whopping 70% of the ATP they consume goes to powering it.

The pump dictates both how and when a nerve impulse fires. It enables the transmission of electrochemical signals that tell your heart to beat, your bicep to curl, and your neurons to receive and interpret sensory data.

I won’t spend long on the inner workings of sodium-potassium pumps. (If you love that stuff—or want a safe and effective sleep aid—grab a biochemistry textbook.) But one key factoid is that for every unit of ATP used, three sodium ions are pumped out of the cell, while two potassium ions are pumped in.

So basically, sodium gets pumped out while potassium gets pumped in. And you need adequate levels of both electrolytes to keep those pumps running smoothly. But most healthy people aren't getting enough sodium, and the vast majority of the population is short on potassium. There are a variety of diet, lifestyle, and other factors that may contribute to these electrolyte deficiencies, but we need to move on.

The point is: when your pumps don’t run smoothly, your body will notice. Let’s get into the more tangible aspects of why electrolytes matter now.

What Electrolytes Do For You

Sodium-potassium pumps are great, but what have electrolytes done for you lately? A lot.

In this section I’ll cover how electrolytes influence energy, heart health, and many other aspects of health. After each brief section, I’ll link to blogs so you can dive deeper into each topic.

#1: Energy levels

There are several ways electrolytes can be said to “give you energy”.

First, electrolytes are essential for cellular respiration. In other words, they help turn stored energy (food) into usable energy (ATP).

Also, sodium and potassium structure the pumps that allow nerve impulses to fire. Do you think this affects your subjective energy? You better believe it does.

Finally, there’s hydration. Drinking fluids without sodium, for instance, is a common cause of low energy and fatigue. That’s why LMNT is so salty.

To learn more, read the blog: Do Electrolytes Give You Energy?

#2: Exercise performance

Athletes can lose up to 7-10 grams of sodium per day exercising in the heat. If that sodium isn’t replaced, performance will suffer.

Often only fluids are replaced. Unfortunately, this dilutes blood sodium levels leading to a dangerous condition called hyponatremia.

About 15% of elite endurance athletes experience the cramps, headaches, confusion, and brain fog of exercise-associated hyponatremia. Some have perished.

To learn more, read the blog: How to Hydrate for Endurance Sports.

#3: Heart health

Sodium-potassium pumps keep your heart beating. Enough said.

Just kidding, I’ll say more. For instance, deficiencies in sodium, potassium, and magnesium have each been linked to poor heart health outcomes.

When it comes to heart health, sodium is the most controversial electrolyte. According to a 2011 JAMA study, the sweet spot for heart health outcomes is around 5 grams of sodium per day, but the government continues to recommend we keep it under 2.3 daily grams. Not exactly evidence-based.

Potassium is less controversial. Inadequate potassium is an obvious cause of high blood pressure, which is a major risk factor for heart disease.

To learn more, read the blog: Electrolytes and Heart Health.

#4: Brain health

For brain cells (neurons) to fire, you need adequate sodium and potassium in and around the cell. I don’t know about you, but I like when my neurons can fire.

Sodium is especially critical for brain health. If sodium levels drop too low, the brain swells with water and a range of neurological symptoms ensue.

To learn more, read the blog: Why Your Brain Needs Electrolytes.

#5: Mood

Closely connected to brain health, consider the following links between electrolytes and mental health:

  • Low serum sodium is well-documented to cause mood swings.
  • When rats are deprived of sodium, they become depressed.
  • Magnesium supplementation appears to help with both anxiety and depression.

To learn more, read the blog: Electrolytes and Your Mood: A Surprising Link.

#6: Immune health

Both sodium and potassium help maintain the electrical charge inside and outside cells. This membrane potential not only allows nerve impulses to fire, but also allows for the transmission of signals that direct your immune system.

Potassium may also cool unnecessary immune activity (aka, chronic inflammation) by inhibiting a pathway called the NLRC4 inflammasome.

To learn more, read the blog: Why Electrolytes Matter for Immune Health.

#7: Hormonal health

The relationship between electrolytes and hormones is a vast, largely unexplored universe. Here are a few examples of how they interrelate:

  • Low sodium status increases stress hormones like cortisol, epinephrine, and norepinephrine.
  • Sodium deficiency provokes the release of aldosterone, a hormone that raises blood pressure.
  • Low thyroid hormones have been linked to low sodium and potassium levels.

To learn more, read the blog: How Electrolytes and Hormones Work Together.

It Was Electrolytes All Along

At the end of every Scooby-Doo episode, the villain is unmasked to solve the mystery. Inevitably, the culprit is a boring character that seemed irrelevant to the plot.

It was Mr. Langerhans all along!

Electrolytes are that boring character in your body, except they’re no villains. Every function you care about—thinking, exercising, breathing, keeping your heart healthy, staying emotionally stable, and much more—depends on the sodium-potassium pump.

Other electrolytes matter too, of course, but sodium and potassium are especially important. They’re the currency of life. They’re the hero behind the mask.

It was electrolytes all along!

The best way to prevent the symptoms that follow low electrolyte intakes are with tasty electrolyte drinks. You can take your pick between these homemade recipes or try LMNT, our convenient and tasty electrolyte drink mix.