Signs and symptoms of right Pranayama practice
Kaniyasi bhavedsveda kampo bhavati madhyame /
Uttame sthanamapnoti tato vayum nibandhayet//(Chapter -2, Verse 12).
At first stage there is sweating, in the middle stage trembling, in the last stage complete steadiness, and therefore the breath should be withheld. (Chapter -2, Verse 12).