SPEAKING OF TAMAS...
The Three Obstacles to the Practice of Yoga-Asana
"The obstacles to becoming an adept yogi are sleep, laziness and disease.
"One has to remove these by the root and throw them away in order to keep the body under one's control, to control the senses, and to make the prana vayu appear directly in the sushumna nadi....."
-Sri Tirumalai Krishnamacharya