The human body’s magnetic field is made up of both positive and negative ions. Over-exposure to positive ions can affect our magnetic field and drain energy, making us feel tired and lethargic. However, water in motion produces abundant negative ions, bringing more energy and vitality.

Negative ions are odorless, tasteless, and invisible molecules that we inhale in abundance in certain environments such as the ocean but also mountains, and waterfalls. Once they reach our bloodstream, negative ions are believed to produce biochemical reactions that increase levels of the mood chemical serotonin, helping to alleviate depression, relieve stress, and boost our daytime energy.

https://www.huffpost.com/entry/how-negative-ions-produce-positive-vibes