If you can afford sacrificing a part of your social life, I really recommend biphasic sleep. On the other hand, if you usually spend your time out in the evening, don’t try it. It would create more problems than it would solve.

Today, I missed my nap because I was eating dinner. Altthough I did take the nap a bit later than usual, I got very tired. I also had troubles waking up — it was definitely more difficult than it usually is. I am stilll tired, and I woke up half an hour ago. Perhaps I should try sleeping now in order to get the sleep schedule right again.

Today is my birthday, and thanks to biphasic sleep, I got up fast enough to make breakfast for myself.

Today, I lingered in bed until a quarter past after the nap, and by then I was still sleepy. I’ll try to sleep 7.5 hours for some time now, and see if it makes it better.

The last 72 hours or so, I’ve only slept a total of six hours a day. I can feel that this is getting back at me already; today, in Physics, I was dead close to falling asleep. I was barely saved by a highly timely nut-cake.

And so, I conclude that I need more than six hours a day to get by. On the other hand, 7.5 hours seemed too much. Perhaps alternating between the two is a good idea.

The nap felt great today. I could get up without any real problems. Also, note that I continue sleeping 4.5 hours of core sleep, and I still feel great.

Wozniak completely refutes polyphasic sleep, calling thos who call themselves polyphasic sleepers liars. However, he seems to say that biphasic sleep is better than monophasic.

• “EEG measurements indicate that humans are basically biphasic.”
• “Human body clock is not adapted to sleeping in patterns other than monophasic or biphasic sleep.”
• “[…] an important biphasic nature of the human sleep that is not fully accounted for by the present sleep models.”
• “Only when approaching substantial sleep deprivation can polyphasic schedule be superior to biphasic schedule [when it comes to maximizing creativity].”
• “Many biphasic sleepers can do well on 4 hours [of sleep a day].”

Come to think of it, I haven’t seen any expert on the subject (except Uberman, the “inventor” of a very strict polyphasic sleep schedule) who promotes sleeping in more than two phases. Fortunately, I’m a biphasic sleeper.

I really had to force me up from this nap. Probably it was because I had given myself 20 minutes to fall asleep, although I fell asleep almost immediately. I have to improve in feeling how tired I am.

The plan with sleeping for only six hours a day is going fine. I didn’t have any trouble waking up after 4.5 hours, but I did stay in the bed for ten minutes or so contemplating whether I’d have enough energy to make it through the day. Needless to say, I never even felt tired until the nap.

Core sleep: 03:00 (or 01:30) - 07:30
Nap: 20:00 - 2130

Of course, this schedule is completely theoretical and impossible to follow to the minute. I always take a few minutes extra time to fall asleep, and I doubt that my sleep cycles are exactly 90 minutes long.