Potassium Levels: What You Need to Know About High and Low Potassium

When your body talks about potassium levels, a vital mineral that helps your nerves and muscles work, keeps your heart beating regularly, and balances fluids. Also known as serum potassium, it’s not just another number on a lab report—it’s a key player in keeping you alive and feeling normal. Most people don’t think about potassium until something goes wrong. But if your levels dip too low or climb too high, you could feel dizzy, weak, or even get heart rhythm problems.

Low potassium, or hypokalemia, often shows up after sweating too much, vomiting, or taking certain diuretics. It’s not rare in older adults on blood pressure meds or people with digestive issues. Symptoms? Muscle cramps, fatigue, constipation, and sometimes a weird fluttering in your chest. On the flip side, high potassium, or hyperkalemia, is sneakier. It doesn’t always cause symptoms until it’s serious—like when your kidneys can’t flush it out because of diabetes, kidney disease, or certain heart meds. That’s when you risk dangerous heart rhythms. Both conditions link directly to how your body handles electrolyte balance, the delicate system of minerals that control nerve signals and fluid movement. It’s not just about potassium—it’s how it talks to sodium, magnesium, and calcium. Your kidneys, gut, and even your hormones are constantly adjusting these levels. A single pill, a bad bout of diarrhea, or even too many salt substitutes can throw things off.

You won’t find potassium levels in every blood test, but if you’re on meds like ACE inhibitors, diuretics, or have kidney trouble, your doctor should be checking. Eating more bananas or spinach won’t fix a serious imbalance, and popping potassium pills without a test can be risky. The real fix? Knowing your numbers, understanding your meds, and watching for signs your body is sending you. Below, you’ll find real-world stories and science-backed advice on how potassium levels affect everything from heart health to muscle function, and what to do when things go sideways.

17 Nov 2025
by Michael Brown
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