Strictness of sleep times

Oversleeping and Crashing

Sleeping at any time which is outside of the desired schedule is known as ‘oversleeping’ or ‘crashing’.  This includes falling asleep at the wrong time, microsleeping for a second to several minutes, or failing to wake up from a nap or core on time. For example, if one sleeps at 12:50-13:10 when their nap is scheduled at 13:00-13:20, they both underslept (ending early) and overslept (starting early) 10 mins. While assessing the adaptation setback from oversleeps is difficult, it is dependant on several factors; how long the oversleep was (longer = more severe), the schedule (less sleeping time = more severe) and adaptation progress (further = more severe). When and how the oversleep happened might also affect the adaptation setback and hardship. An approximation is that oversleeping a nap is a setback of one to a few days, and having a huge multiple hour oversleep (over 100-200% of the total scheduled time, depending on the intensity of the schedule) can be treated as a total progress reset.

Any form of oversleeping is detrimental to adaptation for a multitude of reasons, and results in unhelpful consequences. For example, after a typical oversleep you are only partially cured of sleep deprivation (a minor part at that), so you end up with worse symptoms after proceeding, while the adaptation progress is set back. Oversleeps interfere with the body learning the schedule, and you will cause you to be tired at the wrong times. Oversleeping can easily become habitual, as your body learns that recovering from deprivation by oversleeping/crashing, rather than by adapting to the schedule, is an alternative way to recover the sleep debt. This results in oversleeping/crashing more frequently (OverSleeping Syndrome, OSS). It is common to feel great for a few days after an oversleep (from some sleep deprivation being recovered, usually 1-5 days), followed by a big energy crash, where risking to oversleep becomes very apparent. This feeling usually subsides after about a week (replaced by the usual sleep deprivation symptoms). Also, the increase in total sleep time leads to a reduction in sleep depth and an extension of cycle length, which reduce enhanced sleep quality essential to polyphasic sleep. A common response to oversleeping is temporarily losing the ability to fall asleep for naps or to get REM in the naps, which further increases the risk to oversleeping due to exhaustion.

Learn from each oversleep and make changes, in order to avoid future oversleeps. Getting stuck in Oversleep Syndrome (oversleeping every few days) results in failing to adapt to a schedule and thus constantly being plagued by severe sleep deprivation. Long-term sleep deprivation leads to obesity1, diabetes2, increased heart rate3, headaches4, fatigue5, an increase in negative moods such as anger, hostility, depression, confusion, tension and a decrease in positive moods such as vigor and happiness6, etc…

The solution to cure this syndrome, is to go back to a consistent and complete monophasic sleep pattern until one has regained homeostasis. Usually this takes 1-2 weeks, but this time can shorten/drag out depending on the amount of sleep deprivation), before attempting to adapt to a polyphasic schedule again. See Recovery in Adaptation Methods.

It is very important to sleep at the scheduled times as precisely as possible! Do not get extra naps, do not extend the core, and do not skip sleep if at all possible!

Strictness of sleep times

Once the sleep times have been determined it is important that they are adhered to as well as possible. Since the body does not distinguish between weekdays and weekends the same schedule should be kept all week. It is also important that the scheduled sleep times are followed as closely as possible each day. How strictly the times should be followed is currently being investigated, however during the 2018 fall and 2019 spring daylight savings time shifts the community has conducted tests to monitor how fast schedules can be shifted each day without it affecting the physical and mental well-being of people, and as short shifts as 5m have been noted to have a negative effects for most. While this does not give conclusive evidence that people’s adaptation progress was set back, it still suggests that it is best to stick to the sleep times as tightly as possible. The current community recommendation is to not move the alarm times at all, but instead only go to sleep later if absolutely necessary. This teaches you to prioritize your sleep schedule, and to work your life around the few set strict sleep times, which fosters much needed discipline for the later parts of the adaptation. An added benefit of not moving the alarm times at all is that several pre-set alarms can be stacked long before the scheduled sleep times, which leads to a lower chance of the alarm setup being a reason for oversleeping.

Skipping sleep versus moving sleep

When adapting to a schedule, it should be emphasized that it is important to stick to all sleep times in the schedule tightly for the first month to the best of your abilities, as in going to bed at the same time everyday and avoiding oversleeps. Some small mess-ups should however still be tolerable. Altering the scheduled sleep times should also be avoided if possible, since each permanent change of sleep times will initially bring out the same effects as oversleeping does..

If you know that you are going to miss some sleep it is best to skip rather than to move it, since moving sleep counts as oversleeping, which results in the adaptation being set back. This is because repartitioning requires strict entrainment of sleep times, and moving sleep has been seen to have the same negative effects as oversleeping. Missing the sleep, or undersleeping, is not as detrimental as oversleeping. While it sets the adaptation back after adaptation stage 3, undersleeping does not confuse the body and the entrainment of the schedule to the same degree that oversleeping does. Undersleeping might result in a decreased feeling of tiredness at the usual sleeping times for a few days after the missed sleep, however the alternative is increased tiredness during the day. Of these two options undersleeping is almost exclusively the superior option. It should still be pointed out that losing a nap means an increased the risk of an oversleep later, so be sure you’re prepared for this. Set up extra alarms or ask someone to check on you to make sure you’re awake. It is also important to note that undersleeps should not be compensated for during the adaptation. If you undersleep the optimal coping method is simply continuing the adaptation as normal, not making up for lost sleep at a later time, as that will count as oversleeping.

The one exclusion where moving a sleep yields a better result than skipping it is if you know not doing so will result in an even longer oversleep later. If this happens it is important to make sure the moved sleep is not too close to the next nap or core, leaving a gap of at least 4 hours before the next sleep. If some parts of a core need to be skipped it should be done in chunks of 90 minutes (full cycles) to avoid waking up in the middle of a cycle, which increases the risk of experiencing an SWS wake. If you have to skip your whole core try to at least get some naps in during that time.

If you are still interested in the idea of flexing your sleep and want to get further information, our article about Flexible Sleep Timing might give you the answers you seek.

Main author: Crimson
Page last updated: 23 July 2020

Shoenfeld N, O’Donnell T, Bush H, Mackey W, Callow A. The management of early in situ saphenous vein bypass occlusions. Arch Surg. 1987;122(8):871-875. [PubMed]
Felkel H, Feuereisl R, Tománek A, Janour Z, Mazur O. [The determination of the type of flow in the trachea and the bronchoscopically accessible bronchial tree]. Pneumonologie. 1971;146(2):120-125. [PubMed]
Matsunaga H, Nishimoto I, Kojima I, Yamashita N, Kurokawa K, Ogata E. Activation of a calcium-permeable cation channel by insulin-like growth factor II in BALB/c 3T3 cells. Am J Physiol. 1988;255(4 Pt 1):C442-6. [PubMed]
Blau J. Sleep deprivation headache. Cephalalgia. 1990;10(4):157-160. [PubMed]
Baehr W, Zhang Y, Joseph T, et al. Mapping antigenic domains expressed by Chlamydia trachomatis major outer membrane protein genes. Proc Natl Acad Sci U S A. 1988;85(11):4000-4004. [PubMed]
Davis H, Gascho C, Kiernan J. The skin in magnesium-deficient rats. Arch Dermatol Res. 1975;254(1):1-13. [PubMed]