What Are the Causes of Low Sodium in Healthy Adults?

Hydrate with a sports drink if you're going for a long run.
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You've probably heard all about the bad reputation of sodium, but your body actually needs it. Sodium maintains fluid levels so your muscles and heart can function. Even if you’re generally healthy, some underlying conditions may cause your sodium levels to drop to an unsafe level, a condition called hyponatremia.

Why It’s Dangerous

    Because sodium is so important for heart and nerve function, low levels can be very dangerous. In the early stages, you’ll feel overly exhausted and have headaches. As sodium levels continue to drop, your muscles become weak, you’ll become confused and you could pass out. In very severe cases, you might have to be admitted into the hospital to get intravenous fluids to prevent slipping into a coma.

Vigorous Exercise

    If you’re an avid long-distance runner or often go to many long aerobics classes per week, your sodium levels may be abnormally low. When you sweat profusely, you’ll lose sodium through your skin. In this case, you’ll want to keep a stash of sports drinks nearby to replenish your lost sodium. You don’t even have to be working out to sweat. If you live in a hot climate or tend to spend a lot of time outdoors during summer months, you’ll be sweating and losing sodium. You can also snack on baby carrots or drink low-sodium tomato juice to add healthy amounts of sodium back into your system.


    That seasonal flu is more hazardous than you may realize. When you’re vomiting and having diarrhea for days, you’re losing fluid, as well as sodium. Even though you can’t hold much down, it’s important to hydrate and get electrolytes, like sodium, back into your system. Try drinking an oral electrolyte beverage, either the children’s variety or a sports drink. You can dilute it with water if the flavor is too strong. You’ll still be replenishing some of sodium you lose while you’re recovering.

Other Causes

    Hyponatremia can stem from problems with your kidneys. Your kidneys filter sodium in your body, keeping your levels stable. If your kidneys aren’t functioning properly, your sodium levels can drop quickly. Taking a diuretic, a medication that makes you urinate more often, also causes you to lose sodium. Additionally, low sodium levels may stem from issues with your heart or liver. So, even if you think you’re generally healthy, you’ll need to go through a thorough follow-up if your routine blood panel shows that your sodium is low.

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