Sutra 2.49: tasmin sati shvasa prashvsayoh gati vichchedah pranayama
- tasmin = upon that
- sati = being accomplished
- shvasa = inhalation
- prashvsayoh = exhalation
- gati = of the uncontrolled movements
- vichchedah = slowing, softening
- pranayama = extension and expansion of prana, regulation of breath
Translated loosely into English;
Thus, (when posture is perfected) begins the slowing of the unregulated movements of inhalation and exhalation by means of extension and expansion of breath.
By practicing regulating the breath, lengthening the exhale, expanding the inhale and working on breath control, the physical breath and energetic breath (prana) begin to slow. The fluctuations of the mind are reflective in the movement of prana (and to some extent breath). Through the practice of pranayama, the student becomes focused and the mind is concentrated. As the breath slows, awareness of prana, concentration and meditation deepen, until total awareness of breath is overcome and the student rests in samadhi.