There is a preponderance of your own tendencies in early morning. A sattvika man is sattvika at that time. He will do japa or studies. A rajasika one will jog and exercise. And a tamasika one will sleep at that time. The sleeper is a slave to negative living, while the knower is the master in a positive existence. Tamas is born of ignorance.
Under the influence of tamas, man’s intellectual capacity to discriminate between right and wrong gets veiled, and he starts acting as if under some hallucination or stupefaction. Such a man lives in indolence, heedless of higher purpose, and asleep to the nobler and divine aspirations of life.
There is no consistency of purpose, brilliance of thought, tenderness of emotion, or nobility of action in an individual who comes under the influence of tamoguna.