Sitting in a sauna may be relaxing, but building one could be anything but ... outdoor shower, or hot tub. Celebrities from Gwyneth Paltrow to Joe Rogan have touted their sauna and cold plunge ...

A new business is taking the plunge in Detroit's hot Brush Park neighborhood ... say is a growing market for cold plunge tubs and saunas. The global cold plunge tub market size was estimated ...