Hyponatremia Explained: When Too Much Water Becomes Dangerous

Quick answer: Hyponatremia occurs when blood sodium drops too low—often because too much plain water dilutes the sodium already in your bloodstream during prolonged exercise. Sodium-containing electrolyte drinks may help active people maintain fluid balance during long efforts. Hyponatremia is a medical condition; always consult a healthcare provider for any concerns about sodium levels.

Medical note: This article is for general educational purposes only. If you have concerns about sodium levels, hydration disorders, kidney disease, heart conditions, blood pressure, or any other health issue, talk to your doctor or a registered dietitian before changing your hydration routine.

What Is Hyponatremia?

Hyponatremia is a condition in which the concentration of sodium in the blood falls below the normal range. Sodium is one of the body's most important electrolytes—it helps regulate fluid balance inside and outside cells, supports nerve and muscle function, and plays a central role in how much water your body retains or releases.

When sodium levels drop too low, cells can begin to take on excess water. In mild cases this may cause discomfort; in severe cases it can become a medical emergency. According to MedlinePlus, a publication of the U.S. National Library of Medicine, hyponatremia has several possible causes—including certain medical conditions, some medications, and excessive plain-water intake without adequate sodium replacement.

Salt of the Earth is a zero-sugar electrolyte powder made with Pink Himalayan salt. It is not a medical treatment and makes no claims about treating or preventing hyponatremia. It is a hydration support drink designed for active people who want sodium, potassium, magnesium, and calcium without added sugar.

How Does Drinking Too Much Water Lead to Low Sodium?

Your body works hard to keep blood sodium within a narrow window. When you drink large amounts of plain water in a short period—especially during sustained physical activity—you can dilute the sodium already in your bloodstream. This is sometimes called dilutional hyponatremia.

Exercise-associated hyponatremia (EAH) has been documented among marathon runners, triathletes, and ultramarathon competitors who drink beyond their thirst during long events, relying primarily on plain water. The NIH StatPearls review on hyponatremia notes that consuming hypotonic fluids in excess of sweat losses is a primary driver of dilutional sodium loss during exercise. The National Athletic Trainers' Association (NATA) has issued position guidance on exercise-associated hyponatremia specifically for this reason.

The lesson isn't that water is harmful—it's that balance matters. For activities lasting more than about an hour, or in conditions of heavy sweat loss, pairing water intake with a sodium-containing beverage may help support that balance. This is also a general recommendation from the American College of Sports Medicine (ACSM) in its fluid replacement guidance for athletes.

Who Is Most at Risk?

Research consistently points to several groups who may face a higher risk of exercise-associated hyponatremia:

• Endurance athletes in events lasting two or more hours, particularly marathons, triathlons, and ultramarathons
• Slower-pace participants who spend more time on course and often drink more aggressively than faster athletes who finish sooner
• People who drink beyond thirst during exercise—a behavior once widely promoted but now understood to carry real risks in prolonged activity
• Individuals with certain medical conditions including kidney, heart, or liver issues that affect fluid regulation—always consult your doctor if you fall in this group

Non-exercise hyponatremia also exists and can result from medical causes unrelated to overdrinking. This article focuses on the exercise-related hydration context; for clinical hyponatremia of any cause, please see your healthcare provider.

Sodium's Role in Fluid Balance

Sodium is the primary electrolyte in the fluid outside your cells (extracellular fluid). It helps govern how water moves across cell membranes and how much your kidneys excrete. When sodium is present in sufficient concentration, your kidneys signal the body to excrete more water. When sodium runs low relative to water, excess fluid can accumulate in cells—which is the core mechanism in dilutional hyponatremia.

Potassium works primarily inside cells. Calcium and magnesium participate in nerve signaling, muscle contraction, and a wide range of metabolic processes. Together, these electrolytes maintain the electrical and chemical gradients across cell membranes that underlie everything from a heartbeat to a marathon finish. For a deeper look at cellular-level hydration mechanics, see our article on How Electrolytes Actually Work.

Hydration Options Compared: Sodium, Sugar, and Duration

Whether to use plain water or a sodium-containing electrolyte drink depends on activity duration, intensity, heat, and individual sweat rate. The table below compares common hydration options:

Hydration Option	Sodium per Serving	Sugar per Serving	Best Fit	Sodium Buffer for Long Activity
Plain water	0–5 mg	0 g	Short activities under 60 min in moderate conditions	None—risk of dilution increases with volume
Gatorade Original (20 oz)	~270 mg	~34 g	Moderate-intensity exercise with carb needs	Moderate sodium; high sugar
Gatorade Zero (20 oz)	~160 mg	0 g	Zero-sugar exercise hydration	Some sodium; lower than original
Coconut water (8 oz)	~45–150 mg	~8–11 g	Light activity; potassium-forward option	Low sodium; limited dilution buffer
Salt of the Earth	1,000 mg	0 g	Endurance activity, heavy sweating, zero-sugar preference	High sodium from Pink Himalayan salt; strong support for fluid balance

Label values are approximate. Individual needs vary. This table is for informational comparison only and does not constitute medical advice. Salt of the Earth sodium reflects current product formulation.

Common Questions About Hyponatremia and Hydration

What exactly is hyponatremia?

Hyponatremia is the medical term for abnormally low sodium in the blood (clinically below roughly 135 mEq/L). It ranges from mild—where someone may notice nausea or headache—to severe, which is a medical emergency. Multiple causes exist. Excessive plain-water intake during prolonged exercise is one specific mechanism, known as exercise-associated hyponatremia (EAH).

Can drinking too much water actually hurt you?

In extreme situations, yes. Consuming very large volumes of plain water faster than the kidneys can excrete it—particularly during long bouts of exercise—can dilute blood sodium to low levels. The risk is real but avoidable. Drinking to thirst rather than on a rigid schedule, and including a sodium-containing beverage for activities over an hour, are strategies widely recommended by sports medicine organizations including the ACSM and NATA.

What might overhydration feel like during exercise?

No individual symptom is diagnostic—always seek medical evaluation for any concern. That said, some people who consume too much plain water during endurance events report nausea, bloating, a feeling of fullness that water doesn't resolve, unusual puffiness, or a worsening headache. Because these overlap with many other conditions, prompt medical assessment is important if any appear during or after exercise.

How does sodium help during long workouts?

Sodium is the primary extracellular electrolyte. When you sweat, you lose sodium alongside water. Replacing sodium with fluid helps maintain the normal concentration in your bloodstream and may reduce the risk of dilutional hyponatremia. The ACSM recommends that athletes engaging in prolonged exercise include sodium in their fluid replacement plan—not just water alone.

How much sodium is in Salt of the Earth?

Each serving of Salt of the Earth provides 1,000 mg of sodium sourced from Pink Himalayan salt, plus 200 mg potassium, 60 mg magnesium total, and 40 mg calcium. It is sweetened with allulose and stevia with zero added sugar. The Unflavored version also includes MCT powder.

Are endurance athletes the only group who should think about this?

They are the most extensively studied group in the exercise context, but hyponatremia can affect anyone who consumes very large amounts of plain water rapidly. People with certain medical conditions may also be at risk regardless of exercise. If you have any concerns, your doctor is the right resource.

Where Salt of the Earth Fits

Salt of the Earth is a zero-sugar electrolyte powder built around 1,000 mg of sodium from Pink Himalayan salt per serving. It also provides 200 mg potassium, 60 mg magnesium total, and 40 mg calcium, sweetened with allulose and stevia. The Unflavored version includes MCT powder for those who want a fat source alongside minerals.

Salt of the Earth is not a medical product and is not intended to treat, prevent, or manage hyponatremia or any other medical condition. It is a hydration support drink for active people who want a sodium-forward, zero-sugar option to pair with their water intake during longer or more demanding activities.

For runners, cyclists, outdoor workers, and anyone who sweats consistently, a sodium-containing electrolyte option gives you a way to support mineral balance without adding sugar. That is the straightforward role it plays.

Browse the full Salt of the Earth lineup at drinksote.com/collections/all, or read more about electrolyte science in our Electrolyte Science Guide.

Practical Hydration Principles for Long Activity

These general strategies reflect current sports medicine guidance and are not a substitute for individualized advice from a healthcare provider or registered sports dietitian:

• Drink to thirst. Current ACSM and NATA guidance generally supports drinking when thirsty rather than on a rigid schedule during exercise, which helps avoid overconsuming fluids.
• For activities over 60 minutes, consider including a sodium-containing beverage alongside plain water rather than relying on water alone.
• Know your sweat rate. Heavier sweaters lose more sodium per hour. Sweat-rate testing is a tool used by sports dietitians to personalize electrolyte plans.
• Do not force fluids. Weight gain during a race or long workout is a signal you may be drinking more than you are losing—race medical staff are trained to evaluate this.
• People with medical conditions affecting fluid or sodium regulation should build a hydration plan with their doctor before training for or competing in endurance events.

Frequently Asked Questions

What is hyponatremia in simple terms?

Hyponatremia means the sodium level in your blood is too low. It is a medical condition with multiple possible causes, including drinking too much plain water during prolonged exercise, certain medications, and underlying health conditions. It ranges from mildly symptomatic to a serious medical emergency. See your doctor if you suspect it.

Can you get hyponatremia from drinking too much water during a marathon?

Yes. Exercise-associated hyponatremia (EAH) is well-documented in marathon and ultramarathon runners who drink primarily plain water and consume more fluid than they lose through sweat. It is one reason sports medicine organizations recommend sodium-containing beverages for activities lasting more than one hour, particularly in heat.

What is the difference between dehydration and hyponatremia?

Dehydration is a net fluid deficit—you lose more water than you take in. Hyponatremia is a sodium deficit relative to water—you may have normal or even excess total fluid but too little sodium concentration. They have different mechanisms and different management approaches, which is why proper medical evaluation is essential rather than self-treating either condition.

Does Salt of the Earth help prevent hyponatremia?

Salt of the Earth does not make prevention claims—hyponatremia is a medical condition. It is a zero-sugar electrolyte drink with 1,000 mg of sodium per serving from Pink Himalayan salt, plus potassium, magnesium, and calcium. Active people who want to support their hydration with sodium and minerals during long efforts may find it useful. Medical concerns should go to your doctor.

Is Pink Himalayan salt better than regular salt in electrolytes?

Both Pink Himalayan salt and regular table salt provide sodium chloride as the primary mineral. Pink Himalayan salt also contains trace minerals from its geological origin. Salt of the Earth uses Pink Himalayan salt as its sodium source. For a deeper look, see our article on Pink Himalayan Salt vs. Table Salt.

How much water is too much during exercise?

There is no universal threshold—it varies with body weight, sweat rate, temperature, and exercise intensity. The key guidance from ACSM and NATA is to drink to thirst and to include sodium in your fluid plan for activities lasting more than 60 minutes. Gaining weight during exercise is a reliable signal of overdrinking.

Who should talk to a doctor before using high-sodium electrolyte drinks?

Anyone with kidney disease, heart conditions, high blood pressure, a history of sodium-related disorders, or any condition affecting fluid or mineral balance should consult a healthcare provider before using high-sodium supplements, including electrolyte powders like Salt of the Earth. This is also sound advice for anyone new to endurance sports.

The Bottom Line

Hyponatremia is a real and well-documented risk in endurance sports, driven primarily by drinking too much plain water without enough sodium to keep pace with sweat losses. It is a medical condition that deserves professional evaluation whenever it is suspected—not home management.

The broader takeaway for active people is practical: water is essential, and sodium is your water's partner. For short, easy activities in moderate conditions, plain water is usually all you need. For longer efforts, heavy sweat conditions, or situations where high water intake is not relieving thirst, a sodium-containing electrolyte drink alongside your water may help maintain the balance your body needs.

Salt of the Earth offers one option in that category: 1,000 mg sodium from Pink Himalayan salt, zero sugar, and a full complement of supporting minerals—potassium, magnesium, and calcium—in a portable powder format designed to mix cleanly into water.

Always talk to your doctor about any symptoms related to hydration, sodium levels, or exercise performance, especially if you have an underlying health condition.

Sources: MedlinePlus — Hyponatremia | NIH StatPearls — Hyponatremia | National Athletic Trainers' Association (NATA) | American College of Sports Medicine (ACSM)