Mineral Spotlight: Sodium

Sodium (Na), No. 11 on the Periodic Table, is the sixth most abundant element on Earth, although the metal always shows up in compounds (table salt, for example, is sodium chloride) and wasn’t isolated in the laboratory until 1807, by Sir Humphry Davy, who also isolated potassium. A liter of Iron Mountain Hot Springs water contains about 8,230 mg of sodium, about the same proportion as the ocean. Sodium compounds are used in a wide variety of products. Salt can be a preservative as well as a seasoning, and sodium bicarbonate—baking powder—is used in cooking and in cleaning products.

Inside your body, sodium performs many vital functions. It helps keep the pressure balance between fluids inside and between your cells. It’s involved in muscle contraction and the electrical signals that travel through your nervous system. Too much salt can have negative consequences, especially high blood pressure. Although research on blood pressure has focused on the kidneys, blood vessels and brain, one study demonstrated that salt metabolism in the skin might be an important factor.

Chances are, you’re getting plenty of sodium in your diet—most Americans get too much. On average, we consume 3,400 mg a day, when we probably need more than 1,500 milligrams and shouldn’t have more than 2,300. In addition to table salt, sodium comes in milk, beets, celery, sauces and bouillon cubes; many processed meats and canned foods, as well as fast foods, are high in added sodium. Soaking in the hot spring won’t expose you to excess sodium—it doesn’t absorb through your skin.

The presence of sodium in Iron Mountain Hot Springs does make the water more dense and therefore more buoyant, similar to ocean water that weighs 2.5 percent more than ocean water. That means a cubic foot of salt water can displace 64 pounds, compared to 62.4 pounds for a cubic foot of fresh water. That buoyancy feels good to tired muscles and joints, and it’s part of the total relaxation experience at Iron Mountain Hot Springs.