Do you know what the definition of Yoga is in the language where Yoga originated?
Yoga as a culture in America is founded on the misinterpretation of what people are doing as "yoga" in the far East.
Yoga by definition in those countries where it originated is not a reference to stretching, and balancing ones posture, or moving around once in a while to adjust energy.
YOGA, by definition is an unending event in which all aspects of your life are a portion of it. Yoga, by definition of Sanskrit is Devotional service to God. A healthy lifestyle of being BALANCED and in tune with God the World and Yourself.
If Yoga ends for you, then you factually are not partaking in Yoga. You are stretching, balancing, and moving. This is a flaw in America's education and understanding of culture.
Being in tune with reality and being one with God is a mandatory portion of "doing Yoga". If you are atheist, Yoga is IMPOSSIBLE for you.
Just to clarify the origin and technical definition of the term - regarding this common misinterpretation.