Sweat Like a Celeb! Brad Pitt, Natalie Portman and More Hit the Trails

Can't make it to the gym? Do what Natalie Portman, Fergie and Reese Witherspoon do--take a hike!

Want to stay in shape, but aren't keen on being cooped up in the gym?

We've got three words for you—take a hike! No, really, go out and tackle the trails!

Aside from the obvious aerobic exercise, the uneven terrain is a great way to challenge different muscle groups that you aren't using every day (trust us, after a good hike, you'll feel muscles you didn't even know you had!).

Even with access to all the fanciest fitness classes, there are tons of celebs that love this scenic way to get their sweat on.  

If you live in the L.A. area and want to increase your chances of seeing stars (as in celebs—please don't hike at night if you're looking for the other kind, it's not safe!) Runyon Canyon is a hiking hotspot that you'll definitely want to check out.

Everyone from the Jonas Brothers to Orlando Bloom and Miranda Kerr have been spotted there—even Brad Pitt hits up Runyon Canyon when he wants to get his hike on.

Tell us: Are you a fan of hiking?