Want an easy way to up your calorie burn? Head for the hills.

Taking your current running or walking routine from the comfort of a regular flat route and mixing it up with one that includes a few inclines is an easy way to up your calorie burn by a lot. And that's not the only benefit -- once you've worked hills into your workout, you'll find your speed and endurance will increase, too.

So next time you hit the pavement, don't take the easy route -- you'll get more benefit from challenging yourself.