The mechanics of 20 minutes sleeping

24 hours of solo sailing, heading east along the Tuamotus archipelago, dodging 4 atolls. The boat is running at 6 knots, and if I fell asleep, we could crash catastrophically onto land or boats. Staying up all night seems torturous, though.

People wonder how solo sailors keep a watch when offshore overnight. Personally, I don’t trust my radar to warn me, as some sailors do. The only thing I trust is for my phone alarm to ring, every 20 minutes, telling me, “Wake up dummy, look around, and make sure you’re not about to hit something!”

So I get stirred from my slumber, every 20 minutes, and try to open my eyes and scan the horizon for hazards… and once satisfied, within 15 seconds I fall back asleep. It is almost instant.

While underway, I sleep on my therma-rest in the cockpit bench. When the alarm rings I can simply open my eyes in a stupor, and hazily survey the instruments… wind speed, GPS location, course. Check. Then I’ll look at the horizon for lights & ships, while admiring the stars…the Scorpio constellation rising over the dawn hours… the Southern Cross twirling around Alpha Centauri… and the Milky Way bright as snow in the moonlight. “Oh-oh I see a ship’s light, coming my way!” Ah… common error. It’s just Venus rising on the east, at 3:40am.

Today I feel remarkably refreshed. Certainly much better than spending all night fighting to stay awake.

Is 20 minute interrupted sleep something anyone can do, or only lunatic sailors? My unsupported theory is that if you allow your body to sleep for more than 45 minutes, then you enter REM sleep and it’s really hard to awaken. Perhaps that’s why 20 minute power naps feel so good.

I wonder, however, how the 20 minute sleeping regime would affect a solo sailor (or astronaut?) over several weeks time; whether their bodies would end up fatigued and run-down, and mental functions become impaired… I’d be curious about the studies on interrupted sleeping. If you’re intrigued and have internet, let us know 🙂

Photo: Approximately what I see at 1am with blurry eyes.

8 thoughts on “The mechanics of 20 minutes sleeping

  1. Interesting idea, that REM sleep is harder to wake from. That may well be. I’ll look up “interrupted sleep” and get back to you.

    Not at all the same thing at all, but more grist for the wheel: During my last year at UCLA I attempted to reconfigure sleeping more effectively, “sleep less, but sleep better”. My experiment lasted several weeks: Instead of sleeping 8 or 9 hours, I slept in two daily 4 hour segments. Results: Very poor.. I found REM sleep (dreaming)- generally falling more into the final hours of sleep- is essential to a night’s rest. But there’s more, much more: I found without the beneficial advantages of REM sleep- the collation, organization and analysis that research studies have proven occurs while sleeping- intuition, memory and insight were affected. Negatively. Sleeping less than the normal number of hours (varies of course, by the individual), REM sleep toward the end was lost.

    The first hours of sleep may be important for needed rest, but the last ones that include REM sleep are essential. I’d like to know how 20′ interrupted sleep interacts with needed REM sleep. Will get back to you.

  2. Kristian, wanted to send belated birthday greetings. Can’t tell you how exciting it is to have the Green Coconut Run in my inbox again. Your adventures are so fun to hear about. Glad you had time with your bride. Best wishes as you continue to live out your dreams.
    Love to you, Flora

  3. Getting back to you, Kristian, with news about interrupted sleep. Sorry, but the news is not so good. Research shows: “Those who woke up repeatedly showed less slow wave sleep, or the deep sleep that is normally linked to feeling restored and rested, than those getting the same amount of sleep but in a continuous session. “We saw a drop in slow wave sleep so large and sudden, and it was associated with a striking drop in positive mood that was significantly different than in the other group,” he says.’
    “Why Interrupted Sleep Is Worse Than Short Sleep”

  4. Interestingly and many years ago I was involved in a US Navy study on vigilance and specific deprivation of REM sleep. It is now known that different stages of sleep deprivation can have quite specific effects. The following can result in REM deprivation: reduced ability to consolidate long term memory (from previous day), memory impairment especially spatial memory, amnesia for events following the phase of REM deprivation, reduced judgement (REM sleep seems to modulate and help organize thoughts), increased seizures among epiliptic patients, the effects can last for a surprisingly long time (up to 3 weeks for 72 hour REM deprivation), and there is REM rebound following REM deprivation. Not the types of things we would want for sailors to experience when watching for enemy submarines. However, note that REM periods begin 90 minutes following sleep. At first they are of quite short duration and then become longer as the night progresses. The other major sleep state is Stage 4/Restorative deep sleep that occurs after about about 30 minutes. In contrast to REM the first episode of Stage 4 sleep is the longest and then gets progressively shorter as the night progresses. As the name suggests, this is particularly important for feeling like you’ve had a good nights sleep. So let’s look at Kristian: On the surface it looks like he might have been depriving himself of both Stage 4/Restorative sleep and REM sleep. But then the brain also plays catch-up and tries to rebound into these most crucial stages so he was perhaps able to buffer himself from some of the negative effects. Maybe hook him up to monitors and transmit the results on an upcoming blog?

    • This is super interesting Gary, and yes, offering my body for scientific monitoring is a possibility 😉  Although the study would be much more robust with round-the-world racing sailors who are doing this sleep rhythm for weeks

  5. Brains presumably differ from each other as much do other organs. On a moonless night somewhere in the shipping lanes of the Pacific, let’s hope Kristian’s buffers well to catch-up and rebound to either Stage4/Restorative or REM sleep, whichever at the time is more needed.

    Kristian, if like me you tend to remember dreaming episodes pretty well, when you take your 20′ breaks from sleeping, are you aware which breaks follow REM and which Stage 4/Restorative? If so, a log might be interesting to keep to try to correlate incidence of the two Stages with your diurnal memory, mental acuity and judgement.

    • Yes it does feel like there is some REM / restorative sleep occurring despite the interruptions… to slide back into that sleep state the key seems to be to not be awake long, and quickly fall back asleep.


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