In a (public) Facebook post back in July 2021, I described how I had providentially stumbled into what seemed to be an unusual sleep pattern as I figured out how to work for a company on the US East Coast while living in Singapore:
Boston and Singapore are 12 hours apart most of the year (whenever the US is on daylight savings), which makes the math easy to figure out -- just switch am and pm. I’d always been angling to schedule all of my meetings in the Boston mornings or early afternoons to get to sleep at a reasonable time. Along with a buffer to cool down before sleeping and our regularly scheduled dinners at ~7pm, this gave me a block of about 8 hours I would have to be awake: 7pm to 3am.
For a while, I considered just staying up until 5 to get all of my work in and then sleeping till noon or 1pm, the “college student” lifestyle. But I ultimately found that sleep schedule just too… depressing, I guess I would say. I was also part of a bible study at 8:30am with church friends in the US, and had weekly family calls at 10am, and these didn’t really go well together with that schedule -- I slept through a couple of the bible study gatherings and was rather groggy for some of the family calls.
One week when I did manage to drag myself out of bed for the bible study, I asked my friends to pray that I could find the right sleep schedule for my life here in Singapore. A couple of days later, it just clicked. I started taking long naps in the afternoon and then found myself naturally waking up with the sunrise after a half-night’s sleep at night.
Sleeping in two segments per day falls into the general category of biphasic sleep. By far the most common form is the siesta: a 5-6 hour main sleep block and a 1-2 hour nap in the middle of the day, which is actually fairly common in many Mediterranean and Latin American cultures. That isn’t what I’m doing: The two blocks of sleep are both 3-4 hours, roughly diametrically opposed.
In other words, I’m living life as I listen to podcasts, at double speed.
When I wrote this, I had only been on that schedule for a couple of months. A year and a half later, you might be wondering: Did it last?
The short answer is that it did. Biphasic sleep has become my new default and I expect it will continue to remain so as long as I have the opportunity.
On three occasions in that time, I’ve reverted to monophasic sleep.
In December 2021, I took a two-week vacation with my family visiting Singapore for the holidays.
In June 2022, Grace and I visited the US and I went monophasic throughout.
In October 2022, I experimented with three weeks of monophasic sleep under much more normal circumstances.
While the first two were obviously special, and more or less just proved that it’s still possible for me to adapt to monophasic sleep, it was the last of these experiences that convinced me that biphasic sleep is actually better for me. As I reflected privately:
[Monophasic sleep is] still not that great. I’m reliant on caffeine, needing it to get through the afternoon even after 8 hours of sleep. As I realized, it’s also inherently inflexible and doesn’t work great with my 25-26 hour natural rhythm. With biphasic sleep, I can occasionally skip one of my two naps to get back on track. But staying up late on monophasic sleep is a problem.
That said, the root cause is still the fact that I’m working remotely across the globe. I’d be more fine with monophasic sleep if I didn’t have reasons to be awake after midnight for meetings. But I’m happy to have discovered biphasic sleep as an alternative, and one I’ll probably go back to as long as I’m in this sort of position.
I’m guessing that some of you relate, particularly to the part about becoming reliant on caffeine, which in my case took the form of milk tea, whether mixed up at home from packets, ordered on Grab, or picked up from our local bubble tea store about a 10-minute walk away.
As I’ve shared this schedule with others, I’ve noticed that the tone has changed. At first, many people expressed sympathy, with sentiments like “that sounds rough” or “how much longer are you going to have to do that?” I always insisted that I found this schedule working surprisingly well, although of course I wondered how long it would last.
But after a year and a half, that’s flipped. Having gone back to monophasic sleep for three weeks, I now feel sorry for (the vast majority of) people who can only sleep once a day, especially seeing how much it tends to make them rely on caffeine. Of course, very few of you are in work or school situations like mine that would let you take advantage of this discovery. But if you do find yourself in such a situation, I’d encourage you to try biphasic sleep out!
Over the last five weeks since that monophasic experiment, the one caution I’ve had is that my responsibilities in church, particularly in the youth ministry, were tending to infringe on my Sunday afternoon sleep segment — this had been part of the impetus for trying monophasic sleep out again. As I mentioned in that reflection, I also had found that even with biphasic sleep, when I would fall asleep would tend to shift later and later over the course of the week.
My solution was to try to combine both of these trends: My sleep cycle would shift later and later over the course of the week, before resetting and, aided by bubble tea, dropping one of my sleep segments on Sundays.
Initially I thought a 25-hour cycle would work best, sleeping an hour later each day. I eventually worked out an asymmetric schedule where I’d be awake for 6 hours, asleep for 4, awake for 11 hours, asleep for 4, repeating until I would just be awake for 14 hours on Sundays.
An hour a day turned out to be a bit too aggressive a shift, so I modulated it back to a half hour per day: awake for 6.5 hours, asleep for 4, awake for 10 hours, asleep for 4, and resetting with 17 consecutive hours awake on Sundays.
Meals were another big reason to dial back the precession. I usually have four meals a day (three on Sundays), two in each waking segment, including small bowls of cereal (usually muesli) for both breakfast and supper. Due to coordination with the rest of my family, my dinner time can’t shift much, which meant that the other meals were having to swap which waking segment they fell into over the course of a week. In the less aggressive 24.5-hour cycle, I just shift the timing of those meals by about half an hour a day as well.
So yes, my natural rhythm is not 25-26 hours long, as I thought it was before experimenting with this. I’m entertained that it actually seems to be quite close to 24 hours and 39 minutes, which is the length of a (solar) day on Mars, hence the title of this post.
Just to be clear, I’m not rigidly sticking to this new “Mars time with weekly resets” schedule, as I’ve never had to do with any such schedule I’ve sketched out while on biphasic sleep. In fact, the beauty of this schedule is how flexible it is. In addition to modifications like being able to skip one sleep segment per week, I can also sleep earlier or later than planned by up to a couple hours, and sleep for as short as 90 minutes or as long as 6 hours as needed.
But not much longer. One thing that biphasic sleep actually makes it hard to do is to sleep longer than about 4-6 hours in one stretch. When I do manage to sleep for longer than 4 hours, any subsequent sleep is often the nearly-awake REM sleep phase full of vivid dreams that keep my mind engaged.
It’s become incredibly natural to me but whenever I think about it, I’m genuinely surprised at how I now regularly wake up without an alarm fully refreshed — often before the sunrise! — having slept for only about 4 hours, especially as someone who always thought of myself as a night owl reliant on my alarms.
The best explanation I’ve heard is that the most important sleep phase for feeling well-rested is deep sleep, which tends to attenuate over the course of a typical night of sleep. In biphasic sleep, I’m therefore able to get more deep sleep for the same amount of total time spent sleeping, which is why I tend to feel so well-rested.
Of course, all of this doesn’t mean that I can’t transition between biphasic and monophasic sleep if I need to — it just takes 2-3 days in either direction. The easiest stepping stone between the two is the siesta — a 6 hour main sleeping segment and a 90 minute nap. Just staying up like I do on Sundays doesn’t cause me to flip — I still tend to naturally wake up after 4 hours of sleep early Monday morning, as intended.
Two weekends ago, I tested the flexibility hypothesis when I volunteered with our church’s first youth camp since the pandemic. Youth camps in Singapore are, well, a lot less rugged and distant than in the US — we were still walking distance from a subway station; some of the participants, youth and volunteers, didn’t stay overnight; and we had some of the main church’s worship team visit and lead us in song for one of the sessions.
But like I remember from youth camps in the US, the youth didn’t want to sleep. The first night, because of some misbehavior, everyone was sent to bed before 1am. After I got my usual 3.5 hours of sleep, I emerged and found that a few of the boys were also awake — by 6, the hallway was full of them. My main purpose in being there was to spend more time getting to know them, so rather than shoo them back to bed, we chatted in the hallway until breakfast came out at about 7:30.
Then late that afternoon, I took my leave and napped for about 3 hours. I ended up sleeping through dinner and my roommate and fellow volunteer Joshua noticed and graciously set some aside for me.
That night, the youths were very interested in staying up late. Since I had gotten my afternoon sleep, I was able to chaperone the late night games and discussion, which ended up continuing until 4am. As we put it afterwards, I had “taken the night shift” on the volunteer team.
In a similar vein, as I’ve shared my sleep schedule with various friends, I’ve heard from several of them that it might be quite conducive to taking care of a newborn. As we anticipate the arrival of our first child, a daughter, some time in the next month, the only thing I can say is, we’ll see.