Anything bracing is brisk and refreshing. A Mainer might consider a January swim in the Atlantic ocean to be bracing, while her Floridian best friend may think she's crazy.
You probably enjoy the bracing sea air when you're on a sailboat, or the bracing hike you take up the side of a mountain. In both cases, you're filled with energy and feel fortified by the experience. The adjective bracing comes from the verb brace and its figurative meaning, "to strengthen or comfort."