Electrolytes 101: Why They Matter—and How to Rehydrate Smarter

My Body
Written By Sydney Lawson

(Electrolyte balance isn’t a luxury: it’s a potential lifesaver).

By: Joy Stephenson-Laws, Holistic Coach, J.D., Founder

“Why didn’t football players urinate after a game?”

This was the question that led to the invention of the most popular sports drink of our time — Gatorade.

Back in 1965, University of Florida professor and nephrologist Dr. James Robert Cade and his researcher team posed this question when they noticed University of Florida football players didn’t pee after such vigorous exercise in the hot and humid Florida weather.

“After collecting fluid samples from UF football players, Cade and his colleagues realized the players’ electrolytes were out of balance, and their blood sugar and total blood volume was low. They developed a drink containing salts and sugars that quickly replaced lost nutrients and improved performance,” (Historical Marker Program, University of Florida).

Is the sugar in those neon-colored bottles really serving you? Let’s break it down.

1. What Are Electrolytes—and Why Your Body Depends on Them

You’ve probably heard the word electrolyte tossed around—maybe during gym class when you were a kid or on the label of your favorite sports drink. But electrolytes aren’t just for athletes. They’re vital for everyone in every day life.

Electrolytes are minerals that carry an electric charge when dissolved in body fluids. This electrical energy is how your body communicates: it tells your heart to beat, your muscles to move, and your brain to fire up thoughts. Without electrolytes, nothing in your body would really function.

All electrolytes are considered to be minerals. These minerals work in a sacred balance. Too much or too little of one can throw the whole system off.

Electrolytes are indispensable for:

  • Hydration balance. Electrolytes regulate fluid movement between cells and tissues—keeping you neither dehydrated nor water-logged.

  • Nerve impulses. Tiny shifts in electrolyte concentration trigger the electrical signals that make your nerves fire and muscles contract.

  • pH regulation. Acid-base balance hinges on electrolytes like phosphate and bicarbonate, ensuring optimal enzyme function and metabolic health.

The big electrolyte players include:

  • Sodium (Na⁺)

    • Maintains fluid volume; critical for nerve/muscle function

  • Potassium (K⁺)

    • Regulates heartbeat; works with sodium to transmit nerve impulses

  • Calcium (Ca²⁺)

    • Muscle contraction; bone health; blood clotting

  • Magnesium (Mg²⁺)

    • Muscle relaxation; ATP production; hundreds of enzyme reactions

  • Chloride (Cl⁻)

    • Balances sodium; component of stomach acid (HCl)

  • Phosphate (HPO₄²⁻)

    • Energy transfer (ATP); bone structure; pH buffer

  • Bicarbonate (HCO₃⁻)

    • Primary blood buffer; maintains acid–base homeostasis

Trace elements—like copper, iron, zinc and chromium—also appear in sweat and play supporting roles in cellular metabolism and antioxidant defenses.

Examples of electrolyte imbalance:

  • If you drink too much plain water and dilute your sodium levels, you could experience headaches, confusion—or in extreme cases, seizures.

  • If calcium is too high and magnesium too low, your muscles may twitch or cramp unexpectedly.

Maintaining balance is especially important when you're sweating—whether you're exercising or even feeling anxious (because yes, stress causes mineral loss too).

2. Sweating It Out: How Much of these Electrolytes You Lose

During exercise—and especially in hot or humid conditions—sweat is your body’s air-conditioner. But even a “low” sweat rate of 0.5 liters per hour can carry significant electrolyte loss. Although sweat is 99 percent water, sweat also contains small amounts of sodium, potassium, calcium, chloride and magnesium.

Sweat helps regulate body temperature, but with this comes electrolyte loss.

A landmark review of soccer players found average sweat electrolyte concentrations of:

  • Sodium Na⁺: ~45 mmol/L

  • Potassium K⁺: ~5–6 mmol/L

  • Calcium Ca²⁺: ~0.7–1.2 mmol/L

  • Magnesium Mg²⁺: ~0.1 mmol/L

Total losses per liter of sweat (approximate):

  • Sodium: 1,000–2,000 mg

  • Potassium: 200–300 mg

  • Calcium: 15–50 mg

  • Magnesium: 2–15 mg

Factors influencing sweat rate and composition include exercise intensity, environmental heat, acclimatization status, genetics, body size, and even protective gear.

Real Life Story: Electrolyte imbalance puts young RUNNer on vacation in hospital

Back in 2022, a 33-year-old experienced runner named Morgan Philpott was going for a run on her beach vacation. As a runner who regularly trained, Morgan was used to three to five mile runs and even weekly 10 to 15 mile runs (Business Insider).

Morgan was running for only 30 minutes on the beach, and she was also running early in the morning before the sun got too intense, however, she still experienced quite the vacation downer. Symptoms including nausea, severe headache and confusion (all of these after she stopped running) landed her in the emergency room.

“Humidity and drinking too much water without sodium likely contributed to her illness, according to an exercise science researcher specializing in heat safety,” (Business Insider).

As mentioned earlier, drinking too much plain water and diluting sodium levels could lead to headaches, confusion and, in extreme cases, seizures.

“Over the next two hours, she said symptoms worsened — she was vomiting every few minutes, unable to keep down liquids, and had muscle cramps and jagged lines across her vision,” according to the report from BI.

Fortunately, she recovered after receiving IV electrolytes and anti-nausea medication at the ER. This shows how quickly electrolyte imbalance and heat exhaustion can cause serious problems. If she had not gone to the emergency room so promptly, the outcome could have been much worse.

Would a sports drink have prevented this?

What’s in your average sports drink?

3. Conventional Sports Drinks: Pros and Cons

Most commercial sports drinks are designed to replace what we lose through sweat: primarily sodium and potassium. That’s good in theory—but look a little closer.

A glance at your average 12-ounce sports drink reveals:

  • Water

  • Sugars (30–40 g )

  • Sodium (200–350 mg )

  • Potassium (75–150 mg)

  • Flavorings & acids (citric acid, phosphate)

  • Stabilizers & colors (gum arabic, artificial dyes)

Pros:

  • Rapid fluid replacement

  • Quick carbohydrate source for high-intensity efforts

  • Convenient, shelf-stable

Cons:

  • Excess sugar. 10 tsp per bottle spikes insulin and adds empty calories.

  • Missing electrolytes. Magnesium and calcium often absent or in trace amounts.

  • Artificial additives. Long, unpronounceable stabilizers and dyes provide no nutritional benefit.

4. Spotlight on Magnesium: The “Forgotten” Electrolyte

Magnesium is involved in over 300 biochemical reactions in the body.

So many of these sports drinks contain very little magnesium or no magnesium at all.

Magnesium is one of the most important minerals for your body—and yet, most people don’t get enough. It’s involved in over 300 biochemical reactions in your body. It helps relax your muscles, stabilize your mood, support your sleep, and protect your heart. And when you’re stressed or sweating, you lose even more of it.

Top benefits of magnesium:

  • Cardiac protection. Low magnesium (especially with low potassium) heightens risk of arrhythmias and sudden cardiac arrest. One population study found communities with higher drinking-water magnesium had 38% lower rates of sudden cardiac death 

  • Blood pressure & vessels. Magnesium relaxes smooth muscle in arteries, helping maintain healthy blood pressure (verywellhealth.com).

  • Glucose metabolism. It plays a role in insulin signaling; deficiencies correlate with higher risk of type 2 diabetes (eatingwell.com).

  • Muscle cramp prevention. Adequate magnesium reduces exercise-associated cramps and restless leg symptoms.

The medical term for low magnesium is hypomagnesemia.

A study analyzing the magnesium status of 192 Olympic and Paralympic athletes over eight years found that 22% were clinically deficient in magnesium at least once during the study period. This deficiency was associated with increased risks of tendon injuries and muscle issues, underscoring the importance of monitoring magnesium levels in athletes.

A 15-year-old male athlete experienced over a year of worsening exercise-induced abdominal pain, nausea, and vomiting. Despite aggressive hydration and treatment for presumed gastritis, his symptoms persisted. Upon further investigation, his serum magnesium levels were found to be critically low at 0.7 mg/dL (normal range: 1.6–2.3 mg/dL).After magnesium supplementation, his symptoms improved, and he was told to continue oral magnesium chloride to prevent this from occurring again.

Low magnesium can even contribute to cardiac arrest.

How much magnesium does the average person need?

The Recommended Dietary Allowance (RDA) for adults 19-51+ years is 400-420 mg daily for men and 310-320 mg for women. Athletes typically need 10–20% more magnesium than the average person, though this can vary depending on training intensity, sweat loss, and diet.

Food sources—pumpkin seeds, almonds, spinach, black beans—can supply much of your daily magnesium; but during heavy training, supplemental magnesium (25–50 mg per 8 oz) in your rehydration mix helps fill the gap.

There are many delicious, magnesium-rich foods to enjoy.

5. Smart Hydration Strategies for Athletes

Hydration with electrolyte balance is key!

  1. Customize by sweat test. If you train >4 hours/week, consider a field sweat test to measure your individual losses (National Institutes of Health (NIH))

  2. DIY electrolyte mix. Combine, per liter of water:

    • ½ tsp sea salt (~600 mg Na⁺)

    • ¼ tsp potassium salt (e.g., “NoSalt”) (~400 mg K⁺)

    • 100 mg powdered magnesium citrate

    • Juice of one lemon or orange (for flavor and citrate)

    • 1–2 tsp honey or maple syrup for mild carbohydrate

  3. Choose enhanced sports drinks. Look for “full spectrum” formulas with Mg²⁺ (25–50 mg), Ca²⁺ (20–50 mg), and lower sugar (≤6 g/8 oz).

  4. Time it right.

    • Pre-exercise: 5–10 mL/kg of fluid 2 hrs prior, with a light electrolyte snack.

    • During exercise: 150–350 mL every 15–20 minutes, more in heat/extreme exertion.

    • Post-exercise: 1.5 L for each kg of weight lost, ideally containing 20–30 mEq of sodium.

  5. Monitor signs. Thirst, dark urine, muscle cramps, lightheadedness—these signal you may need more balanced electrolytes rather than just plain water.

6. Beyond the Bottle: Whole-Food Hydration

  • Coconut water. Naturally rich in K⁺ (600 mg/L) and Mg²⁺ (25 mg/L), but low in Na⁺—pair with a pinch of sea salt.

  • Watermelon juice. Hydrating, high in K⁺ and antioxidants—add a dash of salt and scoop of unflavored electrolyte powder.

  • Smoothies. Blend spinach, banana, yogurt, and a sprinkle of salt for a micro-nutrient and fluid boost.

A creamy, green smoothie is a great method for getting magnesium and other vital nutrients

7. Beware Over-hydration: The Other Extreme

Hyponatremia—too much water diluting blood sodium—can cause headaches, nausea, seizures and even death. It’s most common when athletes replace sweat losses with plain water only. Balancing water with adequate sodium—and adding magnesium—prevents this dangerous dilution.

8. Putting It All Together

Electrolytes are more than marketing buzz and popular sports drinks—they’re fundamental to every nerve impulse, heartbeat and muscle contraction. By choosing rehydration strategies that include magnesium (alongside sodium, potassium and calcium), limiting added sugars, and personalizing fluid intake to your sweat losses, you’re not just quenching thirst—you’re fueling performance, protecting heart health, and supporting long-term wellness.

For a deeper dive into the roles of 14 critical minerals in health and exercise, check out Minerals – The Forgotten Nutrient in our Resource Library.

Enjoy your healthy life—powered by balanced electrolytes!

Additional reading & REFERENCES

Sydney Lawson
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