Hyponatremia Explained: Causes, Symptoms & Treatment

Ever felt dizzy, confused, or nauseous after a marathon or a night of heavy drinking? That could be your body screaming about low sodium, or hyponatremia. It’s when the sodium level in your blood drops too low, messing with the balance that keeps your cells happy. Below you’ll find the basics, why it happens, what to watch for, and what to do if you suspect it.

Common Causes of Hyponatremia

Most of the time, hyponatremia shows up when you either lose too much sodium or take in too much water. Endurance athletes, for example, sweat out salts and then gulp down plain water, diluting the remaining sodium. Certain meds like diuretics, antidepressants, or even some over‑the‑counter antihistamines can push sodium out of the bloodstream. Chronic illnesses such as heart failure, liver disease, or kidney problems also trap water, lowering sodium concentration. Even simple things like a salty‑sweat workout without proper re‑hydration can tip the scale.

How to Spot and Treat Low Sodium

Symptoms start out subtle: headache, mild nausea, and a feeling of “off‑balance.” As sodium keeps falling, you may notice muscle cramps, confusion, or even seizures. The key is to act fast—call a doctor if the mind feels foggy or you can’t stay steady on your feet.

Doctors check a simple blood test for sodium levels. If it’s below 135 mmol/L, they’ll look at the cause. Treatment often means restricting water intake for a short period and giving a saline IV to raise sodium safely. In less severe cases, drinking a sports drink with electrolytes can help, but only under medical guidance. Never try to correct it on your own with massive salt pills; the shift can be dangerous.

Prevention is easier than cure. If you’re running long distances, aim for a sports drink that replaces both fluid and electrolytes, not just water. Keep an eye on medications that can affect sodium and ask your doctor if a dose tweak is needed. People with heart, liver, or kidney issues should monitor fluid intake and have regular blood checks.

Bottom line: hyponatremia isn’t just “drinking too much water.” It’s a mix of fluid balance, medication side effects, and underlying health. Knowing the signs, getting quick medical help, and adjusting your hydration strategy can keep sodium levels in the safe zone and protect your brain and muscles from the fallout.