Yoga is the most complete form of mind body spirit exercise. The earlier post responding to the walking sitting posture is correct-but there is more BREATHing. We are not breathing deeply enough and in rhythm with our movements and activities.
Yoga postures are form related, yoga mudra's (hand and arm positions) are energeticrelated, and yogic pranayam is breathing and spiritually realted as it connects all three pieces of the "human" together.
The holy trinity-US! Imagine that!
We are capable of such deep love for each other, and such deep joy in this experience of the flesh and such deep gratitude for this life no matter how unpalatable it may seem at any given moment-Beautiful Ones! It is US!