Put simply Mindfulness means to pay attention to your present emotions, thoughts and sensations as a non-judgemental observer. It enabled me to cope with my high pain levels and physical limitations (and the anxiety and depression that accompanied these) with compassion and acceptance, rather than constantly battling against my circumstances.
There have been numerous scientific studies into Mindfulness which proves that it increases activity in the area of the brain that calms down emotional responses, as well as slowing breathing rate, blood pressure and heart rate.