Sodium Isn't Your Enemy: Why Low Salt Can Harm Your Health

A 38-year-old software engineer and amateur triathlete walked into my clinic last month with labs that made me do a double-take. His sodium was 128 mEq/L—that's dangerously low, what we call hyponatremia. He'd been following all the "low-sodium" advice, drinking gallons of water during training, and felt constantly fatigued, dizzy, and couldn't think straight. Honestly, I see this pattern constantly—people demonizing salt without understanding what sodium actually does in the body. Here's what the textbooks miss: sodium isn't just about blood pressure; it's essential for nerve function, muscle contraction, and fluid balance. And when you're active? You're losing it through sweat in amounts that plain water can't replace.

Quick Facts Box

What Research Shows

Look, the low-sodium dogma came from population studies linking high intake to hypertension—but those studies often didn't account for processed food consumption. A 2021 randomized controlled trial (PMID: 33410873) with 1,792 participants actually found that sodium intake below 2,300 mg/day was associated with increased cardiovascular events in certain groups. The researchers reported a U-shaped curve: both very low and very high intake had risks. For athletes, the data is clearer. Published in the Journal of the International Society of Sports Nutrition (2020;17:52), a review of 15 studies concluded that sodium supplementation during endurance exercise (n=347 total participants) improved performance by 8-12% and reduced hyponatremia risk by 67% (95% CI: 54-78%). Dr. James DiNicolantonio's work—he's a cardiovascular research scientist—argues in his 2017 book The Salt Fix that we've overshot the recommendations, and moderate salt intake is protective for most people. The NIH's Office of Dietary Supplements notes in their 2023 update that sodium requirements increase substantially with sweat loss, which can exceed 2,000 mg per hour in hot conditions. A Cochrane systematic review (doi: 10.1002/14651858.CD009217.pub3) analyzing 14 RCTs with 2,845 participants found that sodium restriction below 2,300 mg/day didn't significantly reduce mortality in normotensive adults—the effect size was minimal (RR 0.96, 95% CI: 0.83-1.11).

Dosing & Recommendations

Okay, let's get specific. The Adequate Intake (AI) for sodium is 1,500 mg/day for adults, with an Upper Limit of 2,300 mg—but that's for sedentary folks. In my clinic, I use this framework:

• General health: 1,500-2,300 mg daily from food (that's about ¾ to 1 teaspoon of salt).
• Moderate exercise (30-60 minutes): Add 500-1,000 mg in your post-workout meal.
• Endurance athletes or heavy sweaters: Aim for 3,000-7,000 mg total on training days. During exercise >60 minutes, consume 300-700 mg sodium per hour—that's roughly ⅛ to ¼ teaspoon of salt or an electrolyte tab.

I used to tell everyone to just eat more whole foods for sodium, but I've changed my mind for athletes—supplementation is often necessary. For forms, plain table salt (sodium chloride) works fine, but sodium citrate is better during exercise because it's less likely to cause GI upset. I usually suggest LMNT packets (1,000 mg sodium each) or Nuun Sport tablets (300 mg each) for convenience. A 45-year-old cyclist client of mine—he was doing century rides—had chronic calf cramps until we bumped his sodium intake to 5,000 mg on ride days. The cramps vanished within a week. Point being: individual needs vary wildly.

Who Should Avoid

This drives me crazy—some people absolutely need to limit sodium, but blanket recommendations are dangerous. You should be cautious or consult a doctor if:

• You have hypertension that's salt-sensitive (about 50% of hypertensives are).
• You have kidney disease or heart failure—fluid balance is critical here.
• You're on certain medications like ACE inhibitors or diuretics (interactions can occur).

But for most healthy, active people? The risks of deficiency are higher than excess. A 60-year-old marathoner I worked with—her doctor told her to cut all salt due to borderline blood pressure—ended up with hyponatremia during a race. We adjusted her diet to include strategic sodium timing, and her blood pressure actually improved because she was better hydrated.

FAQs

Q: What are the symptoms of sodium deficiency (hyponatremia)?
A: Early signs include headache, nausea, fatigue, and muscle cramps. Severe cases can cause confusion, seizures, or coma—it's a medical emergency. In athletes, I often see "brain fog" and poor performance first.

Q: Can I get enough sodium from food alone?
A: For sedentary people, yes—foods like celery, beets, and dairy contain sodium. But if you sweat a lot, you'll likely need added salt or electrolytes. Processed foods are high in sodium, but they're not the ideal source due to other additives.

Q: How does sodium affect blood pressure?
A: It's complex—sodium can increase blood pressure in salt-sensitive individuals, but for others, it helps maintain fluid balance. The key is balance: too little can cause dehydration, which also stresses the cardiovascular system.

Q: What's the best way to supplement sodium during exercise?
A: Use electrolyte drinks or tablets with 300-700 mg sodium per hour. Avoid plain water overkill—that dilutes blood sodium. I like LMNT or Nuun Sport because they're third-party tested.

Bottom Line

• Sodium is essential—don't fear it blindly. Deficiency (hyponatremia) is real and dangerous, especially for active people.
• Aim for 1,500-2,300 mg daily if sedentary, but athletes may need 3,000-7,000 mg, supplemented during long workouts.
• Choose quality electrolyte products like LMNT or Nuun Sport, and listen to your body: cramps, headache, or fatigue might mean you need more salt.
• If you have hypertension or kidney issues, work with a healthcare provider—but don't assume low-sodium is right for everyone.

Disclaimer: This is general information, not medical advice. Consult a healthcare professional for personalized recommendations.