हठयोग प्रदीपिका (योगी स्वात्माराम - ज्योत्स्ना टीका सहित सटीक)

HAṬHAYOGAPRADĪPIKĀ 37 78. The signs of [perfection in] Haṭha-yoga are: Slimness of body, brightness in the face, manifestation of the inner sound (nāda), very clear eyes, freedom from disease, control over the seminal fluid, stimulation of the [digestive] fire and complete purification of the Nāḍī-s.