When summertime rolls around, dietitians recommend paying closer attention to your potassium intake. Potassium is an essential nutrient found in all tissues of the body, according to the National Institutes of Health (NIH), and is required for normal cell function.
Why Potassium Matters in Summer
Potassium plays a key role in regulating muscle function, nerve signaling, fluid balance, blood pressure, and heart rhythm, said Sandra Zhang, a registered dietitian nutritionist at Tufts Medical Center. Low potassium levels can also cause fatigue. Most adult women need about 2,600 milligrams of potassium daily, while men need 3,000 milligrams, per the NIH.
Sweating, common in summer, can lower potassium levels. Data suggests consistent drops in potassium during hot weather, making it important to monitor intake this season.
Potassium and Fluid Balance
Potassium works with sodium to regulate fluid balance, said Laura Acosta, an associate professor at the University of Florida. It also affects muscle contractions, including heartbeats. “Potassium is essential for the heart to beat normally,” Acosta said. Imbalances can cause arrhythmias or, in extreme cases, cardiac arrest. Potassium also helps maintain healthy blood pressure.
Consequences of Low Potassium
Low potassium is linked to dehydration. “Mild deficiency can cause fatigue, muscle weakness and cramping,” Acosta said. Digestive issues like constipation may occur, said Mary Mosquera Cochran, a dietitian at Ohio State University Wexner Medical Center. More severe deficiency can lead to irregular heart rhythms, elevated blood pressure, and dangerous cardiac complications.
Potassium-Rich Foods
Potassium is found in many foods. According to the NIH, top sources include:
- Dried apricots (½ cup): 755 mg
- Lentils (1 cup): 731 mg
- Acorn squash (1 cup): 644 mg
- Baked potato: 610 mg
- Orange juice (1 cup): 496 mg
- Banana: 422 mg
- Milk (1 cup): 366 mg
- Boneless chicken breast (3 oz): 332 mg
How to Monitor and Increase Potassium
There is no easy home test for potassium levels, but diet offers clues, Acosta said. If you regularly eat potassium-rich foods, you likely meet your needs. Persistent symptoms like muscle weakness, fatigue, heart palpitations, or cramps warrant a healthcare visit for possible blood testing.
Cochran suggested using a food diary app to track intake. After sweating, choose potassium-rich foods like bananas, avocados, coconut water, yogurt, milk, beans, lentils, or soy milk. “Adding a pinch of salt or eating salted nuts with a high-potassium food can help balance,” she said.
For most people, a balanced diet compensates for potassium lost through sweat, Zhang said. However, those with clinically low levels may need supplements under medical supervision, as too much potassium can be dangerous.
When to See a Healthcare Provider
If you feel off and have low potassium intake, especially after sweating, try increasing potassium-rich foods. But see a provider for persistent muscle weakness, abnormal heart rhythms, unexplained fatigue, or severe cramping, Acosta said. “These could be potassium-related or something else.”
