Upvote:1
The texts often mention of how the Buddha and many of the Arahants only slept around 4 hours a night. That may sound quite drastic, but they spent most of the rest of the night in meditation, and in my experience personally practicing a significant amount of meditation before bed can reduce the need for sleep down to 4 hours quite easily.
Here are some studies I found on the subject:
Upvote:1
An Arahat does not sleep like a normal person. He may give rest to the body but in doing so is fully aware hence not asleep. This is a natural consequence of reducing impurities of the mind, more particularly the Hindrance Sloth and Torpor. Pacalā Sutta discusses the Hindrance of Sloth and Torpor and methods to overcome it.
Another enemy is laziness, drowsiness. All night you slept soundly, and yet when you sit to meditate, you feel very sleepy. This sleepiness is caused by your mental impurities, which would be driven out by the practice of Vipassana, and which therefore try to stop you from meditating. You must fight to prevent this enemy from overpowering you. Breathe slightly hard, or else get up, sprinkle cold water on your eyes, or walk a little, and then sit again.
...
Similarly, when you go to bed at night, close your eyes and feel sensation anywhere within the body. If you fall asleep with this awareness, naturally as soon as you wake up in the morning, you will be aware of sensation. Perhaps you may not sleep soundly, or you may even remain fully awake throughout the night. This is wonderful, provided you stay lying in bed and maintain awareness and equanimity. The body will receive the rest it needs, and there is no greater rest for the mind than to remain aware and equanimous. However, if you start worrying that you are developing insomnia, then you will generate tensions, and will feel exhausted the next day. Nor should you forcefully try to stay awake, remaining in a seated posture all night; that would be going to an extreme. If sleep comes, very good; sleep. If sleep does not come, allow the body to rest by remaining in a recumbent position, and allow the mind to rest by remaining aware and equanimous.
Source: The Discourse Summaries by S.N. Goenka
Also see: Suppati Sutta
Upvote:3
One of the most common references in the early texts is the wakefulness (jāgariya) pericope:
"And how is the disciple of the noble ones devoted to wakefulness? There is the case where a disciple of the noble ones, sitting & pacing back & forth, cleanses his mind of any qualities that would hold the mind in check. During the first watch of the night [dusk to 10 p.m.], sitting & pacing back & forth, he cleanses his mind of any qualities that would hold the mind in check. During the second watch of the night [10 p.m. to 2 a.m.], reclining on his right side, he takes up the lion's posture, one foot placed on top of the other, mindful, alert, with his mind set on getting up. During the last watch of the night [2 a.m. to dawn], sitting & pacing back & forth, he cleanses his mind of any qualities that would hold the mind in check. This is how the monk is devoted to wakefulness."
-MN 53, Trainee Practice
Notice that, in the second watch, sleep (niddā) is not mentioned. It mentions only lying down on the right side in the lion's posture (dakkhiṇena passena sīhaseyyaṃ kappeti). This could be an indication of not sleeping at all and continuing to practice mindfulness while, at the same time, resting the body.
On the other hand, the absence of the line "he cleanses his mind of any qualities that would hold the mind in check", which is included in the first and last watch, may indicate a less active practice or even sleeping.
I'm sure there are more references regarding this theme but I don't recall any additional ones at the moment.