Potassium is a nutrient, a major mineral, that is necessary for human health. In fact, it is critical to the function of muscle and nerve cells. Potassium plays an important role in regulating heart beat, and a low blood potassium level, known as hypokalemia, may cause muscle cramping and many other symptoms.
Identification
According to the Mayo Clinic, a normal blood potassium level is 3.6 to 4.8 mEq/L. Hypokalemia is life-threatening when potassium levels are at or below 2.5 mEq/L. This requires emergency medical attention. Symptoms of low potassium include weakness and fatigue, constipation, abnormal heart rhythms, or arrhythmias, and muscle cramps.
Causes
Hypokalemia has many possible causes. The most common is excessive loss of this mineral in urine or from the digestive tract. It may be a side effect of certain medications that encourage fluid loss, such as diuretics, excessive diarrhea and/or vomiting, eating disorders, kidney disease and/or excessive use of laxatives. Rarely is inadequate intake of potassium, through diet, a cause for a serious drop in blood potassium levels.
How It Works
According to Sharon Coplin, registered dietitian and Ohio State University Extension nutrition associate in the College of Human Ecology, potassium is an electrolyte--an ionized salt in the body that can become electrically charged. Potassium works with sodium, another electrolyte, across cell membranes to regulate muscle contractions. A blood potassium level that is too low disrupts this process.
Who Is at Risk
In addition to individuals with certain medical conditions or those who take medication that leaches potassium from the body, athletes may be susceptible to muscle cramps from low potassium levels. Those participating in endurance sports or activities, particularly outdoors, such as running, biking, playing basketball or soccer or the like, may be particularly susceptible to muscle cramps. Excessive sweating causes thirst. Drinking water, while recommended, does not replenish electrolytes. Thus, muscle cramping, particularly at night, may occur.
Treatment
The U.S. Department of Agriculture's Recommended Adequate Intake level for potassium is 4,700 mg daily. Those at risk for developing hypokalemia or who suffer from muscle cramps may require more of this nutrient. High-potassium foods include a medium baked potato with skin, which provides 721 mg; 1/2 cup of dried prunes, which contains 633 mg; 1/2 cup of raisins, which offers 600 mg of potassium; and 6 oz. of prune juice, which provides 530 mg. Other potassium-rich foods include bananas, orange juice, cooked lima beans and cooked spinach. Severe hypokalemia requires medical attention.
References
- Mayo Clinic Health: Low Potassium
- Ohio State University Extension: Chow Line: Potassium-rich foods deter muscle cramps
- Linus Pauling Institute: Micronutrient Information Center: Potassium
- Palo Alto Medical Foundation: Potassium Content of Foods and Drinks
- The National Academies Press: Dietary Reference Intakes
