How Much Potassium Is Lost When You Work Out?

Potassium deficiency can cause muscle cramps or injury during exercise.
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Most people know to drink water to rehydrate themselves during and after tough workouts, but they often forget to replenish the electrolytes lost through exercise. Potassium, the primary electrolyte in your body's cells, aids in the proper function of your muscles and nerves. When potassium is lost through exercise, you can experience potassium deficiency, resulting in a number of uncomfortable symptoms or even muscle injuries.

Potassium's Role in Exercise

Potassium is an important electrolyte located inside the cells in your muscle fibers. It helps transport glucose to your muscles' cells and works with sodium and chloride in your body to properly regulate your body's water balance. When the glycogen in your body is broken down to give you more energy for a prolonged or difficult workout, your muscles lose potassium. Potassium, like the other electrolytes in your body, leaves your body mostly through urine and sweat.

Potassium Loss

Whether you're an athlete or not, if you're exercising large muscle groups for more than 30 minutes at a time, such as weight lifting, running, playing a sport or working out to a fitness DVD at home, you are considered to be performing an endurance workout, and you need to pay attention to possible potassium loss. The average adult loses 100 to 200 mg of potassium per hour of endurance activity. Proper replenishment can help you avoid muscle cramps or injuries.

Replenishing Potassium

The recommended daily potassium intake for an average adult is 4.7 grams per day. Fortunately, a number of foods you consume daily are rich in potassium, including meats, dairy, fruits and vegetables. Chicken, fish, buttermilk, milk, yogurt, carrots, celery, sweet potatoes, avocados and bananas are just a few of many foods that contain over 300 mg of potassium per serving. If you believe you need help reaching the recommended daily potassium intake, talk to your doctor about taking a potassium supplement. For every one to two hours of endurance exercise, you need 200 to 300 mg of additional potassium, about as much as a single cup of orange juice or one banana. Eating foods high in potassium before exercise can help you maintain the proper amount of potassium in your cells and prevent the symptoms of potassium deficiency. According to Colorado State University, sports drinks are not good sources of potassium.

Signs of Potassium Deficiency

Potassium loss from your muscles during exercise can cause damage to the muscle tissue. Symptoms of potassium deficiency include nausea, vomiting, muscle spasms, muscle weakness or muscle cramping. A lack of potassium can also slow down or stop your muscle and nerve actions. If you sweat or urinate often throughout your exercise, it may be wise to consume a serving of potassium-rich food before your workout and replenish your potassium during and after as well. Consult your doctor before making major changes to your diet or exercise program.

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