As a physician with almost 20 years of experience in health care, I can honestly say that cold plunges should be regulated. Section R392-302-33 of the Utah regulatory code already outlines the specific use of hydrotherapy pools. In addition to normal pools regulations, hydrotherapy pools are “exempt from all other requirements of R392-302, only if use of the hydrotherapy pool is restricted to therapeutic uses and is under the continuous and direct supervision of licensed medical or physiotherapy personnel.”
The Finnish people tout the therapeutic benefits of a hot sauna, followed by a cold plunge into a lake. And they would know. They're credited with starting the practice and have been doing it for centuries.