About This Answer
A questioner notes that many who practise on four hours of sleep still nod off in meditation, and asks what makes the difference. Ajahn Dtun replies that drowsiness shows concentration is not yet strong enough to overcome that hindrance; it is a normal stage requiring effort and patient endurance. Those whose minds settle easily may need only two or three hours, because the mind rests in concentration.
He recalls his own early struggle. Fearing evening hunger, he ate a large meal, and the heavy sticky rice of the northeast left him very drowsy. Having given his word not to rest during the day, he held out, then became firm with himself about the cause, and over time found that about 30 mouthfuls suited his practice. Each person, he concludes, must experiment to find the right balance of food, sleep and formal practice for concentration to arise.