The changing fall foliage makes this time of year perfect to get out into the great outdoors for a hike. It's a great way to exercise with friends, or just go out alone and enjoy nature. It's a more appealing way to get in a workout than plodding along on the treadmill or running down a busy city street - and hiking definitely is a workout. {relatedarticles}Even if you go as slow as 2 miles per hour, a 150-pound person can still burn up to 240 calories an hour. For women, hiking on a slight incline can help prevent osteoporosis by building strength, plus trails are gentler on the joints than pavement. Before you get out there, be sure you have the right shoes - running shoes with slick tread are not the best choice for hiking.