The most common mineral in seawater is chloride. Not to be mistaken for chlorine, “Chloride is one of the most important electrolytes in the blood,” according to the University of Michigan School of Medicine. But what does it do for our health, specifically? According to U of M, “It helps keep the amount of fluid inside and outside of your cells in balance. It also helps maintain proper blood volume, blood pressure, and pH of your body fluids.” Chloride accounts for about 55% of the mineral content in seawater.

Next, there’s sodium. And although sodium has gotten a bad rap in recent years because of how it contributes to hypertension, some amount of salt is actually necessary and even beneficial for our health. Just ask James DiNicolantonio, PharmD and author of The Salt Fix. In an article written for mbg he explained that, “When our bodies become depleted in salt, the brain seems to react by sensitizing the reward system—and not just the reward system for salt, but the same reward system that drives us to other pleasurable activities.” In other words, salt can make us feel satisfied.

Finally, there’s magnesium. This mineral is responsible for just under 10% of the mineral content in seawater. Magnesium is affectionately nicknamed nature’s “relaxation mineral” for it’s anti-anxiety and stress-busting properties. In fact, Epsom salt baths are a form of transdermal magnesium therapy and have been used to centuries for anything from wound healing to treating spasms and digestive issues.

Of course, getting these health benefits would rely on these minerals actually absorbing through the skin or being ingested while you’re swimming. Still, it could explain why so many of our health woes can be improved by taking a quick dip in sea.