Does Adding Salt to Your Water Make it More Hydrating?

You probably add salt to almost everything you consume—from eggs and steaks to fruits and Happy Hour cocktails. But if you’ve browsed social media lately, you may have seen videos of influencers putting salt in their drinking water. Supposedly, salt makes the water more hydrating and provides certain health perks you can’t get from plain H2O alone.

That’s a bold claim, considering we’ve always been told to “drink at least eight 8-oz glasses of water daily” to stay hydrated. Then again, there was no medical evidence supporting that age-old advice. And despite salt being long demonized for “health reasons,” experts now say we need it (and not just water) to hydrate properly.

In light of this, some people may opt for salted water as their go-to hydration source. But is this something the rest of us should consider? We dove deep into the science to understand why salt matters so much for hydration, the potential dangers of overhydration, and the problem with overly low-sodium diets. Let’s break it down.

What is Salt?

Salt is a natural compound comprising about 40% sodium and 60% chloride (hence why it’s also known as sodium chloride). Sodium and chloride are electrolytes, which means they conduct electricity when dissolved in water or body fluids like blood.

The body relies on this electric charge to perform various vital processes. For instance, “Electrolytes like sodium, chloride, magnesium, and potassium are necessary to deliver fluids to your cells,” says Dr. Natasha Trentacosta, a sports medicine specialist and orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute. “If you lose them by excessively sweating at the gym, for example, it really can throw things off,” she adds.

Where Does the Salt in Our Bodies Come From?

We get most of our salt from our diets. However, how much we intake varies based on what and the amount we eat and drink. According to the American Heart Association (AHA), “About 15% of sodium is naturally in some foods, including celery, beets and milk. Many people add it while cooking and eating. The additions only account for about 11% of total sodium intake.”

The AHA also points out, “Sodium is often added in packaged and prepared foods, such as canned soups, lunch meats, and frozen dinners — either as salt or other common forms of sodium such as baking soda. Overall, more than 70% of the sodium we eat comes from processed and restaurant foods.”

How Does the Body Lose Salt?

As we go about our day, our bodies are constantly flushing out essential electrolytes through normal bodily functions like urinating, breathing, crying, sweating, or sickness involving vomiting or diarrhea. When fluids leave your system, sodium is expelled (which explains the saltiness in sweat and tears). However, how much sodium your body excretes mainly depends on your lifestyle.

Say you’re a hardcore athlete putting in long training sessions, sweating profusely day after day, and sticking to a low-carb diet. You’re rapidly depleting your sodium reserves with nearly every workout. Compare that to someone who spends most of their time in a cool, air-conditioned room and follows a diet with lots of carbs. They don’t sweat as much and expel sodium as quickly. Neither are they losing excess sodium through urine due to their high-carb diet (we’ll explain this later).

Bear in mind that the body can’t produce sodium or store it beyond a certain point. Therefore, you’ll need to consume it daily to replace what’s lost and keep the levels topped up.

How Does Salt Improve Hydration?

What is Hydration?

Before discussing the role of salt in hydration, let’s get a few things straight. One quick Google search for “What is hydration?” and the first few definitions will sound pretty much like this: “Adding water back to the body that’s been lost to keep it functioning correctly.” or “Having adequate water in the body tissues.” Notice what’s wrong with those descriptions? (Hint: they only mention “water.”)

While water is vital for hydration, it’s only half of the equation (and only one of four factors influencing hydration). A more accurate definition for hydration—like those found on medical websites or in physiology books—would instead refer to fluid balance. This fluid in question consists of water, electrolytes, blood plasma, proteins, and other soluble particles called solutes. However, let’s zero in on electrolytes for a moment.

The Sodium-Hydration Connection, Explained

Not because you drink a ton of water means you’re hydrated. If you urinate as much as you drink, that water passes through your system without hydrating it. In fact, many people can consume less H2O and are more hydrated than others guzzling water all day. It all has to do with the composition of the water—specifically, the amount of sodium and potassium in it.

Dr. Bastian explains how this dynamic duo influences hydration: “Acting like a magnet, sodium [and potassium] draw water into cells, a critical factor in maintaining hydration. This process ensures that water properly moves in and out of cells, supporting essential bodily functions.” Or, as personal trainer and S&C coach Nikki Gnozzio puts it, “All the salt [and potassium] is doing is kind of being that bridge from the outer cell to the inner cell so that you can utilize the water more.”

Does That Mean Adding Salt to Water Hydrates You More?

That is the case, according to Dr. Joe Whittington, a Board-Certified Emergency Physician, who confirms that adding a little salt to water can help you get hydrated better: “Sodium is an electrolyte that helps regulate fluid balance in and out of cells. When you sweat or become dehydrated, you lose water and electrolytes, including sodium. Adding a small amount of salt to water can aid rehydration by helping replenish these lost electrolytes.”

But Shouldn’t You Be Avoiding Salt?

The anti-salt craze dates back to the 1980s when research found that high doses of sodium spiked the blood pressure in salt-sensitive rats. Still, there was no proof that normal sodium intake had the same effect on blood pressure in all humans.

Even without that crucial evidence, the government urged residents to avoid sodium to reduce the risk of heart problems. This set off decades of salt-shaming and fearmongering that’s still going strong today—despite multiple subsequent studies finding no link between normal salt intake and high BP in general populations.

Interestingly, some research showed that low salt intake (below the suggested 2.6 grams daily) was more dangerous than moderate levels for most people’s heart health. So, depriving your body of this critical electrolyte could seriously backfire.

Scientific Research on The Impact of Low Sodium on Blood Pressure

• After analyzing over 10,000 people in general populations across 52 centers worldwide, the landmark 1988 INTERSALT study showed no consistent association between moderate sodium intake and high blood pressure.
• A meta-analysis in 2014 found that people consuming under 2.6 grams of sodium daily faced a higher risk of heart disease and death compared to those having a moderate 2.6-5 grams.
• According to the 2017 Framingham Offspring study, healthy adults without hypertension had higher blood pressure on low-salt diets below 2.5 grams per day compared to moderate salt intake.
• Finally, the 2020 Cochrane review found that low-salt diets could lower blood pressure by a small four mmHg in white people with hypertension; the researchers warned that deficient sodium levels could be more dangerous than helpful for most folks.

Today, the World Health Organization (WHO) and other agencies are dead-set on slashing global salt consumption, seemingly convinced that the suggested limit of 2.6 grams a day is a surefire way to prevent high blood pressure and other heart problems worldwide.

The Dangers of Drinking Too Much Water

We’re all familiar with the “8×8” rule that encourages us to chug vast amounts of water, as it’s presumably the key to staying healthy and hydrated (and a reminder that caffeine and alcohol don’t count). But, according to Dr. George Chiampas, an emergency medicine specialist at Northwestern Medicine, “[Drinking too much water] is possible, especially among endurance athletes who drink lots of water quickly.” Dr. Chiampas also warns that “Doing so can disrupt the body’s balance of sodium and potassium and lead to potentially fatal water intoxication.

Overhydration and Hyponatremia

When you overdrink beyond thirst, you may flush out too much of the sodium from your, depleting the sodium levels to dangerous lows and possibly leading to hyponatremia. Common symptoms of hyponatremia include:

• Nausea and vomiting
• Loss of energy, drowsiness, and fatigue
• Muscle weakness, spasms, or cramps
• Disorientation, restlessness, or irritability

Drinking more water if you already have hyponatremia is even more dangerous. The increased water will further dilute your blood sodium levels, possibly leading to cerebral edema, pulmonary edema, and death. While most people won’t overhydrate to such a scary degree, the risk is higher for avid recreational exercisers (primarily females).

The Risk of Exercise-Associated Hyponatremia in Athletes

Shockingly, around 15 out of every 100 endurance athletes may experience some degree of exercise-associated hyponatremia (EAH). The reason? Health organizations like the American College of Sports Medicine (ACSM) have made the public so afraid of dehydrating that many overhydrate instead.

Per ACSM guidelines, endurance athletes are supposed to drink enough water to limit body water losses to no more than 2% of body mass. This advice was based on findings from an overwhelming majority of studies (like this one) that reported hypohydration can impair performance or lead to potential health concerns.

While you should always avoid drinking too much water, remember that mild to moderate dehydration during exercise can impact athletic performance significantly. However, EAH poses a much more severe risk, as it can have potentially life-threatening consequences. Even mild sodium deficiency can notably affect one’s quality of life (think headaches, fatigue, and nausea). Therefore, certain groups need to make every effort to get enough salt.

Who Needs More Salt in Their Diet?

For the average person, 2-3 teaspoons of salt (4-6 grams of sodium) per day hits the sweet spot. However, certain groups may need to increase their salt intake intentionally:

1. Athletes

Athletes who engage in strenuous exercise or physical activity for extended periods lose more fluids as they sweat and respire more. Given the importance of salt for hydration (as discussed earlier), athletes need to replenish those electrolyte losses to prevent EAH and boost their performance.

Sodium helps the body absorb and retain more fluids an athlete drinks, maintaining blood volume and reducing strain on the cardiovascular system. Besides, a 2015 study found that athletes who adequately replaced the sodium lost in their sweat finished a middle-distance triathlon an average of 26 minutes faster than those who didn’t. A year before, distance athletes reversed dangerously low sodium levels by simply drinking salt water in a randomized controlled trial.

Athletes who don’t replenish lost electrolytes (particularly sodium) are more likely to experience fatigue, muscle cramps, and other issues that impair athletic performance.

2. Those Living in Extreme Climates

People living in hot, humid environments tend to sweat more, losing more fluids. Research found that individuals can lose up to 0.5-1 liters of sweat per hour in temperatures of 25-40°C (77-104°F). It’s not just water that’s depleted but also body salt. Salt losses over a typical working shift could be as high as 10-15 grams and may increase the risk of hyponatremia if not replaced adequately.

People living in colder places may need more salt, too. When it’s freezing outdoors, they may not feel as thirsty as in warmer temperatures and don’t hydrate as much. This suppressed thirst can increase the risk of dehydration, disrupting the balance of electrolytes in the body. Similarly, the cold, dry air, indoor heating systems, and warmer gear can increase sweating and respiration, making them even more dehydration-prone.

So, whether you live in a tropical or desert region or a cold climate, you must consume enough fluids and sodium to stay hydrated.

3. People on Low-Carb Diets

Following a keto or low-carb diet provides many health benefits—weight loss, reduced diabetes risk, and improved cholesterol levels, to name a few. However, keto foods are naturally low in sodium, so keto-eaters are often more prone to hyponatremia.

As Diabetes.co.uk explains, “There are some changes with fluid balance that can typically occur within the first couple of weeks of a ketogenic diet. This happens as the body uses up its stored sugar (glycogen), which releases water into the blood that gets passed through urine. As fluid is passed out of the body, salts in the body can also deplete. As a result, you may experience a loss of fluid and salts as you move into and maintain ketosis.”

Like keto dieters, those on low-carb diets may also need more salt. That’s because low-carb diets often cause the kidneys to excrete more fluids and sodium from the body, Dr. Nancy P. Rahnama, a bariatric and internal medicine doctor in California, notes. “With the start of the keto diet, the body switches from using sugar as a source of energy to using the body’s stored fat,” Rahnama points out. “In the process of breaking down fat, the body produces ketones, which are then removed by the body through frequent and increased urination.”

Final Thoughts

Guzzling a bunch of plain water isn’t the hydration holy grail portrayed in many health campaigns. You also need ample electrolytes, especially sodium, so your body can absorb and use the water.

For most of us, a little extra salt here and there does the trick. However, increasing sodium intake could be the secret to staying hydrated for those prone to considerable electrolyte losses through exercise, extreme climates, or low-carb diets.

If you’re not a fan of salty water or sports drinks, sugar-free electrolyte mixes provide the perfect combination of electrolytes you need to feel and perform your best. They usually also come in various delicious and refreshing flavors.