Tapas (Self-Discipline)

Yoga Sutra
II.43: kaya indriya siddhih asuddhiksayat tapasah
“Self-discipline (tapas) burns away impurities and kindles the sparks of divinity.”1
Tapas is the fuel a practitioner needs to maintain the first two niyamas: purity (saucha) and contentment (santosa). It provides the endurance to persevere with yoga practice. 

The yoga teacher Rolf Gate’s in his book Meditations From the Mat defines tapas in several ways: a burning zeal in practice, an enthusiasm for health, gratitude, a sense of wonder, and respect. Another yoga teacher, Richard Freeman explains that tapas ". . .is the light and luminosity that arises when we finally set limits for the activities of the mind."3

Tapas is found in two different contexts in The Yoga Sutras. It is the first part of Kriya Yoga in Sutra II.1.  Then it is found again as the third niyama in Sutras II.32, 43.

Tapas tip:

Yoga postures, proper diet, breathing exercises, and really any exercise like swimming or jogging can be a form of tapas, because they help discipline the body.