Revisiting the Mindfulness and Stress Reduction Connection

While preparing a training for professional caregivers, I was  looking for a simple explanation of the connection between mindfulness practice and stress reduction. What happens during the intimate process of practice that makes it possible to reduce one's stress level? Also, what do we mean by stress?

Floating in my mind were memories of explanations I had read about dukkha - sometimes translated as stress - in the Buddhist teachings, lectures from Jon Kabat-Zinn on MBSR, and scientific interpretations from neuroscientists like Philippe Goldin or Richard Davidson. Nothing that quite captured what I was after, though.

True to the spirit of mindfulness practice, I turned inside and this is what I found:

Stress happens when there is tensing against the flow of life - against the ending of what felt good, against the arising of unpleasant experiences, or in anticipation of their imagined occurrence. It manifests as tensions in the body, and tightness in the mind.

Mindfulness is an iterative process, about becoming aware of these tensions, and relaxing them slowly. Going back and forth between seeing, and relaxing, seeing and relaxing. Insight, or wise understanding facilitates the process of relaxing. Also important is bringing an attitude of relaxed alertness to the practice, so as to not further compound the stress, the tension. 

This is my experience of how mindfulness practice leads to stress reduction.