Hiking -- some define it as simply putting two feet down in rhythm, and so it is. It is walking extended in terms of time and glorified by specialized gear, which brings it in touch with a universe of diverse topics.

1. This is a diet sport. Putting those two feet down in front of each other for an hour on level terrain burns 400 calories. On elevated terrain, it burns 900. Figure in some of the rock or wood obstacles along certain paths and the numbers rise.

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2. This is an exercise sport. Not only does hiking build leg muscle; it trains the cardiovascular system. Those fortunate enough to hike in hilly or mountainous terrain almost immediately elevate their heart rate upon beginning an ascent and easily reach oxygen debt. A 500-foot rise such as those common in Maryland's Catoctin Mountains offers up to 30 minutes of aerobic training, while a 1500-foot climb like that at British Columbia's Maligne Lake yields well over an hour's worth, enhanced by the weight of a daypack.