Thoughts on Segmented Sleep

[M'Boy]

After more than 2 months I have access to a gym. However, due to my work schedule and other commitments I have to wake up around 4 AM to get my workout. To manage my rest properly I am going to try out segmented sleep. In short, I will sleep for four hours twice a day. Given that a regular sleep cycle is around 1 1/2 hours, I should be getting an adequate amount and quality of sleep. Thoughts?

[Matt James]

It probably will work okay. I did this when I worked in a UPS sort facility on the 2am to 9am shift. I wasn't training at the time but the work was demanding (working on the "irreg" line: all the heavy, odd sized shit).

I would recommend trying to fit your sleep times to multiples of 90 minutes though. So either 4.5 hours each, or maybe one 3 hour and one 4.5 hour. In my experience you'll feel more rested even with two 3 hour sleeps than you would from two 4 hour sleeps, due to the interrupted sleep cycle at the end of the 4 hour block.

[Torsten Bauer]

After more than 2 months I have access to a gym. However, due to my work schedule and other commitments I have to wake up around 4 AM to get my workout. To manage my rest properly I am going to try out segmented sleep. In short, I will sleep for four hours twice a day. Given that a regular sleep cycle is around 1 1/2 hours, I should be getting an adequate amount and quality of sleep. Thoughts?

I am not a sleep expert by any means but I can share my recent experience with sleep segmenting. We had our second child in February, and having made the experience of how painful a lack of sleep can be from the first child, we made some adjustments this time. I went to bed at about 8pm with my older child and got up at about 12pm and then went back to bed at about 3am to 7am when my older child wakes up. So I got about 6-7 hours in two segments. I trained during that time three times a week and made great progress on a rather simple program like:

Day 1: Press 3 x 5 + 1 x 8-12, Squat 3 x 5, assistance if time
Day 2: Bench Press 3 x 5 + 1-2 x 8-12, Deadlift 1 x 3-5 + 1 x 8-10, assistance if time
Day 3: Medium Press 5x5, Medium Squat 5x5, assistance if time

Also, I read that a couple of hundred years ago a biphasic sleep was the norm. There is also a Wikipedia article about it: Biphasic and polyphasic sleep - Wikipedia

[Hayden-William Courtland]

We don't have a lot of data on this particular type of segmentation, but based on the data we have, I would say you will run into some problems. First, you will likely not be getting the optimal type and amount of sleep. Normal sleep architecture for humans over a continuous 8-hour span shows variations among each of the sleep cycles therein. For example, the first 2-3 cycles generally put the individual all the way in to slow wave sleep (SWS) where memory consolidation happens. The later cycles then put individuals largely into deep sleep (Stage 2). So a long sleep span gives you different exposures to different types of sleep domains. Yetton et al., 2018 (PMID: 29641599) has a neat paper on this. Second, not sure how you plan to break up the 2x four hour blocks, but you will likely run into circadian rhythm issues. This is another area that is getting more research exposure right now as we are seeing evidence that altering these rhythms can have effects on human physiology (i.e, night-shift workers often have issues with blood sugar control).

[R.S.Malesko]

There appears to be substantial evidence indicating that, before artificial lighting was inexpensive enough to be widespeard, segmented sleep of about two 4-hour chunks per night was actually the common, "natural" way to sleep. This idea is based on widespread surviving references to "first sleep" and "second sleep." See for example The myth of the eight-hour sleep - BBC News

Note that segmented sleeping also isn't too terribly different from cultures with a built-in siesta, or late afternoon post-meal nap.

[M'Boy]

I'm quite familiar with the irreg' line. I worked at UPS for a summer loading the regular trucks. My world for a better functioning fan. I've been playing with the lengths and I have settled on a 3/5 hr split.