I've been thinking about this prompt a bit more. My first answer was the obvious answer that I am most aware of my body when I am exercising.
But then I started to look at my past. I didn't practice that much sports as a child. Some ballet and tennis as a young child and horse-riding as a teenager was all the sports I did. I hated the hours of sports in school from the bottom of my heart. They triggered migraines since we always had to do gymnastics in which you end up upside down. And when we were not doing gymnastics, we had to play ball sports, which was a complete failure for me since I have virtually no depth sight.
As a teenager, I felt most integral body and mind when I was playing music. Especially when playing the cello, because you need to wrap your entire body around the instrument to play. Sometimes I feel complete when I sing too. Not when I am neatly singing from sheet music or singing in the choir, but mostly when I can sing along freely with a song I really like. I remember feeling integral during the pop singing classes I took.
Thinking about this made me realize I should make more time to sing freely and play the cello for 2011.