The good news is that, technically, this <i>is</i> sustainable, for certain values of “sustainable”. I have been sleeping about 6 hours per night on most nights for a decade, basically ever since my kids were born.<p>The bad news is that you’ll never be at peak powers in this way. You’ll be ok enough to go through the day, but with diminished focus and willpower. The few days I make sure to sleep more, I clearly get extra energy and focus. (I then typically pull a 32-hr day because I don’t feel tired, which is also bad).<p>I compensate with afternoon naps when I can, which I think is the best “natural” remedy. My grandfather comes from a culture where you’d traditionally wake up very early, work the fields, then rest in the early afternoon because it’s hot outside, before doing another shift into the cool evening. My dad was lucky enough to invent a job for himself that allowed a similar routine, with 1hr or 2hr naps on most days. Unfortunately, the modern workday was “invented” in Northern Europe and follows different rhythms, so less people get that option than ever before.<p>Other ways I’ve found to increase the sleep-hours count:<p>— allocate a couple of hours during the night for actual work, then go to bed earlier. E.g. 21-3 sleep, then 1 or 2h awake, then another 3h sleep to wake up at 8. (I sleep better in cycles of 3h). This is actually more relaxing to me than doing 9h straight. Unfortunately it’s risky - if you get in the zone, the temptation to skip the second sleep-block is very high.<p>— when you wake up, 30mins physical exercise followed by shower, then back to bed. Surprisingly effective but not always an option (partner or kids in the house will not appreciate the noise).<p>— reducing caffeine. I don’t drink caffeine after 2pm, ever.<p>— losing weight. My amount of fat tends to be inversely proportional to the hours I sleep.