#63 | chr01 – Experiment on the “zeitgeber” and polyphasic sleep

Hi everyone!

One month left for the project, thesis and for a traineeship report. I don’t really have free time these days, but I am really enjoying what I am doing even if it is really complex and frustrating on the first hand. Anyway, I am rushing a bit because I really want to finish everything before mid-May, so I won’t talk too much about the details on what I’ve done these past three days. Recently, I’ve talked about chronobiology stuff, you know? I’ve also said I’ll share with you some data about my circadian clock experiment, so here it is!

For the context, it happens that my student room has a window oriented to the East and if you read the scientific article written by Phillip G. Mead about “Architecture as Environmental Medicine”, it is the best orientation for a natural light to enter your room in the morning. You can understand why I haven’t let the opportunity get away from me. So, for one month, I’ve stopped to use my wake-up alarm, the only natural way for me to get up was the natural light going through the window. I have also written down my feelings every day.

fig.01 – correlation between asleep and awake phase over time

The first week, I’ve tried to get used to this new sensation of dizziness so I haven’t tried anything new in the experiment. The second week, I got up early and at the middle of the experiment, I went to the CERN and hack challenge with Bach, so you can see a “blank spot” in the data. The third week, the pace changed in my school so I’ve tried to follow with the first week “wake up” method. I didn’t feel dizzy anymore and I’ve even felt better than before, in fact, my work was more productive with a polyphasic sleep phase. Then, I needed to go back to Belgium and my room is oriented to the West side of my house, I don’t know if it is because of this orientation or because I’ve changed from a different room that makes me feel a lot more tired than before, however I’ve broken my circadian rhythm.

On the graph you can observe that sudden change the first week: I was so tired to go to sleep at 3 am that I needed to go to bed earlier than before. Then, the black spot was a white night, I don’t really sleep that week, however, I’ve tried to wake up early with the 1h shift. At the end of the week, I’ve returned to the rhythm of the first week but even if I changed my pace, 4 days later, I was able to get up at the same time but I didn’t feel dizzy anymore Finally, I moved from my place and I was completely unsynchronized.

What I can say from that result is: sunrise and sunset don’t really affect my “night owl” chronotype but helped me to synchronize and knowing exactly the time even if I didn’t check the clock (it is my circadian rhythm, my zeitgeber that synchronized after only 3 days). I can also say that if I slept earlier, I can wake up earlier in 4 days later straight. Consequences: my body only need 3 days to accustom to a change of biological rhythm. 2 weeks after the experiment, I can say that I am feeling a lot better than using my alarm clock. I could also wake up at an “earlier” or a “later” time if I needed with a polyphasic sleep phase. However, if my environment changed, the result is immediate and I felt tired and unsynchronized again.

Polyphasic sleep 

Generally, people used to sleep in a monophasic sleep (one night sleep). However, it is possible to sleep in separated “sequences” to be able to get less sleep time but more efficient rest. In fact, there are a lot of ways to sleep in polyphasic sleep, but it is in the same purpose: trying to get the sleep time shorter and the rest more efficient depending on your time/work schedule.

What did I learn?

  • Experimenting the zeitgeber
  • Understanding the disruption pace when the environment is different
  • Full-control on the “wake-up” time after the second week
  • Trying a polyphasic sleep at the same time as the zeitgeber experiment


Mead, Phillip. G., “Architecture as Environmental Medicine,” Proceedings of the 84th ACSA Annual Meeting, Washington, DC, ACSA Press, 1996

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