Since beginners can only remain in contact with the object of observation for short periods, initially one should meditate in brief sessions even eighteen times a day; in due course stability will be achieved of its own accord, at which time the session can be lengthened. It is important not to try at first to meditate for long periods; otherwise, upon sight of the meditation cushion, one will feel nausea and laziness. The session should be left while it is going well, when one still feels that it would go well if continued.
Jeffrey Hopkins, Meditation on Emptiness
buddhism, meditation, shamatha, zazen, zhinay