Salt: A New Path to Heart Resilience

Your body’s sodium levels are linked to your risk of heart problems, but salt intake isn’t the best way to manage them.

Salt has been villainized for decades—it gets blamed for high blood pressure, heart disease, and stroke. But what if the story is more complicated?

Sodium plays a crucial role in the human body. It helps conduct nerve impulses, contract your muscles, and maintain fluid balance in your cells. Without it, our bodies just don’t work.

But too much sodium can, in fact, lead to cardiovascular problems. A new study sheds some light on how much sodium is too much and finds that even normal amounts of sodium can be a risk factor.

Plus, the research offers some insight into a surprisingly simple way to keep sodium levels in check.

The Surprising Science of Sodium, Hydration, and Heart Health

The study, published in the European Journal of Preventive Cardiology, looked at over 400,000 individuals across a 20-year timespan. The researchers looked at two different markers of sodium in the body: serum sodium and tonicity.

• Serum sodium is a measure of how much sodium you have in your blood.
• Tonicity is a measure of how water moves in and out of your cells. 
• Both simple blood tests give doctors an idea of the fluid and electrolyte balance in your body.

Looking at over 20 years of medical data, researchers found that both serum sodium and tonicity can be used to predict hypertension and heart failure. As these measures go up, so does your risk of cardiovascular disease.

One of the most surprising findings was that sodium levels within the normal range could be linked to increased risk. The normal range of serum sodium is 135–146 mmol/L—but your risk starts going up at 140 mmol/L.

So, even if you’re in the normal range, you may have an increased risk of cardiovascular disease.

So, what can health-conscious people do to keep their risk low? You might guess “eat less salt.” And that’s not exactly wrong, but there’s a surprising habit that will help you even more: drinking enough water.

Hydration Is More Effective in Managing Serum Sodium Than Salt Intake

Serum sodium and tonicity can be affected by sodium intake, but the authors point out that proper hydration is an even better way to keep your sodium levels in check. Here’s a line directly from the study:

“differences in fluid intake have a greater effect on serum sodium concentration than differences in salt intake, suggesting that hydration status is likely the main contributor to serum sodium concentrations.”

The takeaway here is clear: if you want to keep the sodium in your blood in check—and reduce your chances of high blood pressure and subsequent heart failure—you should be drinking enough water.

Research also shows that underhydration is linked to accelerated aging and premature mortality from other causes. Not drinking enough water can really get in the way of building the healthier future we’re all about here at Super Age.

It’s worth noting that certain conditions can affect your serum sodium. And, in these cases, you may need to do more than just drink more water.

Underhydration is linked to accelerated aging and premature mortality from other causes. 

“Serum sodium levels can be abnormal in heart failure and kidney diseases,” says Filippo Crea, editor-in-chief of the European Heart Journal. If you have a history of heart or kidney issues, you may want to get your sodium levels tested more often and respond with more than just better water-drinking habits.

In general, though, he says, high serum sodium is an indicator of dehydration. And the solution to dehydration is usually to drink more water.

How to Hydrate for a Healthy Heart

Drinking enough water can help you fend off hypertension and heart failure. Because it also contributes to cognitive sharpness, a positive mood, and metabolic health, it’s basically an all-in-one healthy aging strategy.

So how much should you drink? We have a guide to hydration that will help you figure it out, but you can get started with some basic recommendations.

“In the absence of cardiac or kidney diseases, high serum sodium levels indicate dehydration, which can be easily corrected by drinking more water (at least 1.5 L/day),” says Crea. That’s just over six cups.

If you’re active or in a hot environment, drink more. Sipping throughout the day, even when you’re not thirsty, can keep your body’s fluid stores topped up.

Crea also points out that as we age, our thirst signals get a bit weaker, so you may want to drink a bit more than you feel like you need.

Dr. Jonathan Rabinowitz, professor at Bar-Ilan University and first author of the study mentioned above, recommends a simple test for hydration: “I think the simplest thing people can do is to check their urine color,” he says, adding that it should be “pale yellow.”

His advice is simple: “If it’s darker, drink more.”

It’s Still Worth Thinking About Sodium Intake

This study makes it clear that hydration is crucial for maintaining electrolyte balance for heart health—and the experts we talked to agree. But that doesn’t mean you should stop think about your salt intake.

The study points out that if your sodium levels are high, you should probably combine better hydration with monitoring your salt intake.

And the foods highest in sodium are things you should be having in moderation anyway. Research shows that pizza, white bread, processed meat, and savory snacks are significant contributors to sodium intake in the United States. These kinds of foods may also have preservatives, trans fats, and other things you won’t find in lists of research-backed foods for longevity.

As long as you emphasize minimally processed foods with a focus on vegetables, whole grains, and lean meats, your sodium intake shouldn’t be much of a problem. Especially if you’re drinking enough water.

How to Test Your Sodium Levels

If you’re worried about the sodium level in your blood, you can ask a doctor to test it. Serum sodium is included in the basic metabolic panel (BMP), which is something you should have done every few years.

There’s no specific test for serum tonicity—the authors used a formula to calculate it using serum sodium and glucose (if you’re curious, the formula is 2[Na + (mmol/L)] + glucose (mg/dL)/18). Serum sodium is easier to use, so you probably don’t need to worry about this—but, if you’re curious, you can ask your doctor to calculate it or use your test results.

Getting your sodium levels tested and keeping your salt intake in check definitely isn’t a bad idea. But your body is really good at regulating its electrolyte balance—as long as you’re drinking enough water.

So keep sipping, and know that every glass of water you drink is a step toward a healthier future.