Matsyasana creates a great expansion and stretching of the chest which helps relieve upper respiratory congestion as well as benefits the heart. Additionally, the sinus are drained and opened from the inversion of the head, stretching of the neck and pressure placed on the top of the head. The thyroid and parathyroid glands are stimulated as well
Since this is not a difficult posture, it is recommended that you breathe normally while holding it for between two and four minutes. Repeat it two or three times.
