Runners and non-runners often ask this question - my answer is yes, so it's good to have it endorsed by Malin Svensson, a Swedish former national track and field athlete in this article that appeared on American news website, Huffington Post. 

With the correct technique you swing your arms and push yourself forwards with your poles, engaging the muscles in your upper body.  Most people hardly move their arms when they walk so, "I feel it in my arms", is a common comment from beginner nordic walkers.  It's said positively as they begin to notice the benefits.  "I walk more purposefully" and "I'm taking longer strides" are other frequent observations.

You'll always use more energy by walking faster or for longer, or over hillier terrain.  If you take lessons then you'll also ensure that your technique is as effective as can be so that you get the most out of your excercise, at any level of fitness.