Proper levels of potassium are critical to how your heart and brain function. Low levels of potassium can interrupt electrical signals that drive the brain, causing confusion, sluggish thoughts and brain fog. The body tightly regulates potassium, so low potassium -- or hypokalemia -- is rare. The most common causes of potassium loss are medications, such as diuretics, and disease.
How Your Brain Works
Although the brain is often compared to a computer, the electrical signals function very differently. Your brain contains tens of billions of neurons, each forming connections, called synapses, with thousands of other neurons. When stimulated by sensory information or other neurons, an electrical signal called an action potential spreads throughout the neuron. The action potential causes the release of chemicals called neurotransmitters that spread information to surrounding cells. The pattern of neurons firing action potentials is responsible for producing thoughts and actions.
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Potassium in the Brain
The action potential in neurons depends on electrolytes, mainly sodium and potassium. Low potassium levels cause your brain to slow down. Neurons with low potassium require more stimulation before firing an action potential and cannot fire action potentials rapidly. You may experience this as fatigue, confusion or the inability to start actions or finish trains of thought. The symptoms may be informally called brain fog and will not be corrected by taking stimulants, rest, good nutrition or removing stress.
Most people obtain sufficient potassium from their diet. Diuretics -- drugs that promote urination and water loss -- are the most common cause of potassium deficiency. Certain antibiotics and other drugs can also cause potassium loss. Loss of a large amount of body fluid though vomiting, diarrhea, excessive sweating or other causes can also cause potassium loss. Kidney disease, hormonal disorders and other diseases can prevent the kidneys from keeping potassium in the body.
A small deficiency in potassium may not cause any symptoms. Symptoms of moderate hypokalemia include irregular heart beat, muscle breakdown, confusion, constipation, fatigue, muscle weakness and paralysis.
Sources of Potassium
Many foods contain significant levels of potassium. Foods with high potassium include bananas, milk, granola, kiwi, Lima beans, oranges, beans, tomatoes and all meats. The National Institutes of Health recommend that adults consume at least 4.7 grams, or 4,700 milligrams, of potassium per day. Your doctor may recommend a different intake level based on your health and current medications. Taking potassium supplements orally or intravenously should only be done under a doctor's supervision.