Once the Exalted One spoke to the Venerable Maha-Moggallana thus: "Are you drowsy, Moggallana? Are you drowsy, Moggallana?" — "Yes, venerable sir."
(1) "Well then, Moggallana, at whatever thought torpor has befallen you, to that thought you should not give attention, you should not dwell on it frequently. Then it is possible that, by so doing, torpor will disappear.
(2) "But if, by so doing, that torpor does not disappear, you should think and reflect within your mind about the Dhamma as you have heard and learned it, and you should mentally review it. Then it is possible that, by so doing, torpor will disappear.
(3) "But if, by so doing, that torpor does not disappear, you should learn by heart the Dhamma in its fullness, as you have heard and learned it. Then it is possible...
(4) "But if, by so doing, that torpor does not disappear, you should shake your ears, and rub your limbs with the palm of your hand. Then it is possible...
(5) "But if, by so doing, that torpor does not disappear, you should get up from your seat, and after washing your eyes with water, you should look around in all directions and look upwards to the stars in the sky. Then it is possible...
(6) "But if, by so doing, that torpor does not disappear, you should firmly establish the (inner) perception of light: as it is by day, so also by night; as it is by night, so also by day. Thus with a mind clear and unobstructed, you should develop a consciousness which is full of brightness. Then it is possible...
(7) "But if, by so doing, that torpor does not disappear, you should, conscious of that which is before and behind, walk up and down, with your senses turned inwards, with your mind not going outwards. Then it is possible...
(8) "But if, by so doing, that torpor does not disappear, you may lie down on your right side, taking up the lion's posture, covering foot with foot — mindful, clearly conscious, keeping in mind the thought of rising. Having awakened again, you should quickly rise, thinking: 'I won't indulge in the enjoyment of lying down and reclining, in the enjoyment of sleep!'
"Thus, Moggallana, you should train yourself!"
— AN 7:58