Answer transcribed from Brightway's interview with Dr. Cristen Gordon (pt.1):

There are two different benefits to doing that. If you're doing exercise which increases the heart rate, that just increases nutrients going to the brain, which promotes nerve healing but you don't have to have your heart rate elevated in order to make improvements. Walking is a great exercise if you're doing it mindfully. If you're walking and you're using “bad techniques” or if you're using compensations, your brain learns how to do those compensations. If you get with a physical therapist who can help show you the correct pathways or the correct ways to use your muscles, that helps improve the connections in the brain to your muscles.

For example, maybe you're walking and having a hard time lifting your foot up and there's weakness, or maybe it's a timing issue where you're just not lifting your foot up at the correct time. your brain will create other ways to get your leg through your walking pattern. That might be using increased muscles at the hip or at the knee to make up for the fact that you can't lift your foot. A physical therapist can show you ways to train the right timing and the strength to be able to lift your foot up. That could be through exercises, using splints or bracing, or electric stimulation. There are many techniques a therapist could use to train your brain how to do that, but the goal is to overcome the compensations and learn the correct technique, or the “normal walking pattern” to help the brain regain those pathways.