What Electrolyte Is Opposite Potassium?

You need potassium for muscle function, but it doesn't work alone.
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Electrolytes are powerful minerals that stabilize fluid levels all over your body. Potassium is one type of electrolyte that works side-by-side with sodium, another electrolyte. These minerals work so hard to sustain fluid pressure around cells that they actually burn calories in the process. Many fruits, vegetables and whole grains give you healthy amounts of both types of electrolytes, so it shouldn’t be difficult to get what you need from a balanced diet.

How They Work

    Everything in your body – skin, organs and tissues – is made up of cells. In order for cells to function, they need an equal amount of pressure from fluid on the inside, as well as the outside. Potassium levels are much higher in the fluid inside each cell, while the majority of sodium in your system is just the opposite – outside of cells. Both potassium and sodium cross cell membranes if they need to in order to balance fluid, which is known as the membrane potential. Maintaining membrane potential is a major process in your body, taking up roughly 20 to 40 percent of your resting energy expenditure, or REE for short. The resting energy expenditure varies from person to person, but it is the amount of calories your body burns supporting digestion, neurological functions, your heart rhythm, the membrane potential and many other processes that go on in your body.

Why They’re Important

    Potassium and sodium’s job of maintaining the membrane potential is important for sustaining life. Regulation of these minerals is essential for a regular heartbeat and muscle contractions, as well as for sending nerve messages throughout your system. Your kidneys work hard to filter potassium and sodium. If your kidneys aren't working properly, your potassium and sodium levels might plunge, resulting in an imbalance in fluid. If your potassium levels run low, you’ll have an irregular heart rhythm, known as arrhythmias, weak muscles and intestinal issues. Abnormally low sodium levels can lead to brain swelling, muscle cramps and fainting.

Potassium and Sodium Recommendations

    Because potassium and sodium are vital to basic everyday functions, you need a large amount of each one on a daily basis. You need 4,700 milligrams of potassium per day throughout your adult life, unless you’re nursing. In this case you’ll have to up your intake to 5,100 milligrams daily. You can have up to 2,300 milligrams of sodium each day, although if you have high blood pressure, a family history of heart disease or are over age 50, you’ll have to decrease your intake to 1,500 milligrams per day, according to the Dietary Guidelines for Americans 2010.

Getting Too Much

    Even though you need a lot of potassium and sodium each day, getting too much of either one is detrimental to your health. A high potassium level, known as hyperkalemia, leads to tingling in your limbs, weak muscles and arrhythmia. Too much sodium also affects your heart. Your body holds on to a lot of fluid, forcing your heart to pump harder to get blood to your arms and legs. As a result, your blood pressure spikes, wearing down your heart and arteries. You’ll be more at risk of developing heart disease later on in life. You’re not likely to have too much potassium in your body unless your kidneys aren’t functioning properly, but you can overdose on a potassium supplement. On the other hand, it is possible to get too much sodium from your diet if you eat a lot of salty foods or tend to season everything with the salt shaker.

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