“Have you ever met anyone who regretted taking a good, hard day hike? Me neither.

“There’s something special about moderately paced movement through nature that leaves one feeling refreshed, renewed, and satisfied. Because of that, hiking is rarely considered a sport in the same way as trail running or mountain biking, both of which are more acutely painful and taxing on the body. And yet recent studies show that a walk in the woods—especially at the right tempo—is a superb way to build endurance and strength.”

Brad Stulberg, Outside Magazine (11 September 2017) Full article here :
https://www.outsideonline.com/2238741/most-underrated-endurance-workout-hiking