It is self-evident that the behaviors which take place while an organism is awake are necessary, complex and diverse. As sleep is biologically essential, an excess of time spent awake is considered sleep deprivation, and there are serious physiological and psychological consequences both for individual stretches of wakefulness and serial preference for wakeful activity rather than sleep.
As a state of awareness It is traditional within oriental schools of thought and in esoteric teachings (i.e. antroposophy) to distinguish between four modes of awareness: wakefulness (conferring with dhyana), dream (conferring with dharani, sleep (conferring with pratyahara) and moment of death or absorption of spirit (conferring with samadhi). Each of these modes of awareness (citta) may be exercised (i.e. Yoga) in order to enhance wisdom (prajna) and enlightenment (buddhi). In Yoga these four modes of awareness, mental energies, are united with corresponding life forces (pranas. The mental states of wakefulness, Dhyanas, are corresponding to the Asanas, the commonsensical understanding of Yoga exercises, but specifically refers to the corporeal conduct or seat of the wakefulness.