The one in search of adventure, thriving on the thrill of connecting with nature is the fulfillment of living in the moment, really enjoying the present. A sense of accomplishment and connection is tapped into and it is a truly satisfying experience on so many levels. It's spiritual!
If anxiety is human, maybe adventure seeking is one active form of meditation. While occasionally stressing the joints, it eases the cluttered mind through clear focus on the act at hand; fishing, flying, skiing...etc.