Electrolytes are nutrients that provide electrical prompts to muscles, including the heart, to activate their function. Potassium is one of these nutrients. A low potassium level, called hypokalemia, affects the rhythm of the heartbeat. This may cause sudden cardiac arrest, or SCA, a condition in which the heart muscle stops working. This is not the same as heart attack, which the American Heart Association defines specifically as a blocked artery causing the heart to stop beating. SCA, however, is a serious condition, and people recovering from a heart attack are at risk of having SCA.
Normal Potassium Levels
A normal level of potassium in the blood is 3.6 to 4.8 mEq/L, according to the MayoClinic.com. A very low level is less than 2.5 mEq/L. However, the normal range for potassium is influenced by levels of your other electrolytes; these are almost always tested together. This blood test is commonly done if you are taking diuretics or have other chronic medical conditions that affect your heart or kidneys.
Dehydration and Low Potassium
A common cause of low potassium is dehydration, or the lack of adequate fluid in your body. Taking diuretics, which makes you urinate more, is one potential cause of dehydration. You may also become dehydrated if you sweat excessively, are ill and have diarrhea and vomiting, or if you have an eating disorder, Crohn's or kidney disease. Some symptoms of low potassium are weakness and fatigue, muscle cramps, constipation and an abnormal heart rhythm.
Getting Enough Potassium in Your Diet
It's very unusual for people to need potassium supplements because potassium is so common in the diet. Foods with potassium include all types of meat, salmon, cod and flounder, dairy products and legumes. If you need to watch your weight, focus on eating some of the many vegetables and fruits that are good sources of potassium including bananas, grapefruit, oranges, melons and prunes. Talk to your health care provider before taking potassium supplements.
Dangers of Too Much Potassium
Too much potassium, called hyperkalemia, can be just as dangerous to your heart as too little, because it also affects how the heart muscle works. Hyperkalemia results when your kidneys aren't able to process enough urine, so potassium and other electrolytes build up in the bloodstream; this is more common in older people. Injury, infection, kidney disease and some medications can cause high potassium levels.
Other Effects of Hypokalemia
Researchers are studying other potentially serious effects of low potassium levels, such as having high blood pressure or increasing your risk of having a stroke. One study showed a link between potassium levels and bone health, according to the University of Maryland Medical Center. Additionally, research published in January 2010 in "Circulation: Heart Failure," a journal of the American Heart Association, indicates that even mild hypokalemia can produce an increased risk of death or hospitalization in patients with heart failure and chronic kidney disease.
