Неустойчивая адаптация
Возможны случаи, когда график после адаптации дестабилизируется. Некоторые события, травмы или вещества могут разрушить адаптацию. Ниже описаны несколько типов дестабилизации сна или причин, по которым человек может оказаться в нестабильном состоянии адаптации.
Низкое общее время сна
Обычно очень трудно адаптироваться к графикам с низким общим временем сна, поскольку требуется намного больше компрессии сна, в результате чего остается значительно меньше легкого сна. Это делает расписание гораздо менее гибким и в целом нестабильным, потому что любое внешнее воздействие, которое временно увеличивает потребность во сне, необходимом для восстановления, может легко нарушить адаптированное состояние. Вероятно, это основная причина того, почему долгосрочными полифазниками чаще становятся те, кто придерживается графика, который сокращает сон совсем немного, в то время как большинство адаптаций к nap-only являются непродолжительными.
Also, schedules which reduce sleep greatly require much denser blocks of sleep during the day because of the wake time reduction. Shorter wake gaps are required, which makes such schedules inconvenient for daily life and thus unstable long term. These types of schedules may be destabilized by missing naps too many times or flexing too much/too far due to scheduling conflicts that arise due to the frequent sleeps.
Increased sleep needs
Sleep needs can be increased temporarily, usually as an effect of needed physical recovery. Such cases include increased physical activity[1][2] and some substances such as cannabis[3] or alcohol[4]. External events such as these sometimes may significantly increase sleep needed (mostly SWS) which can shake the adapted state with increasing intensity inversely proportional to the total sleep time of the schedule. This is the main reason why schedules with at least 3 sleep cycles are commonly recommended[5] in the polyphasic community for those with intense physical activity, as they more likely guarantee the possibility to accommodate enough SWS in core(s).
In some cases, REM sleep can be increased as well. Causes may include depression[6] or intense mental activity[7]. The latter is still controversial, because other studies[8] have shown no connection between REM duration and mental activity such as studying intensity.
Flexing
Polyphasic sleep schedules usually become flexible after adaptation. The potential extent of one's flexing ranges and frequency depends on the scheduled total sleep time and the stability of their adaptation. Schedules with lower total sleep time are generally are much less flexible than schedules with higher total sleep time, as flexing is known to decrease sleep quality which is unacceptable for the schedules with extreme compression. However, this varies greatly from person to person based on sleep needs, duration of stable adaptation, and experience with flexing. When sleep is flexed too often and/or too far, the adaptation can be destabilized or even ruined if the compression cannot be maintained anymore.
An adaptation to flexing is required, and one should only flex once they have gradually increased the flexing range over time once the sleeper is adapted to the schedule and all other flexed sleeps, and their sleep is stable. Flexing too much or too fast is likely to destabilize adaptation as well, which happened to some members of the polyphasic discord community.
Sleep time changes
In a similar vein to flexing, a schedule may be destabilized due to sleep time changes. Examples include the time shift that occurs as a result of Daylight Savings Time, time zone changes as a result of travel, or changing sleep times without a proper flexing adaptation first. These shifts can cause a desynchronization between a sleeper's circadian rhythm and their schedule, which cause similar changes to sleep quality that flexing may have, but often on a greater scale. The farther one shifts a sleep, and the more sleeps they shift at once, the higher their chances of schedule destabilization are.
References
- ↑ Erik Naylor, MS, Plamen D. Penev, MD, PhD, Larry Orbeta, BA, Imke Janssen, PhD, Rosemary Ortiz, Egidio F. Colecchia, MS, Moses Keng, MS, Sanford Finkel, MD, Phyllis C. Zee, MD, PhD (January 2000). Daily Social and Physical Activity Increases Slow-Wave Sleep and Daytime Neuropsychological Performance in the Elderly. Sleep, Volume 23, Issue 1, January 2000, Pages 1–9, https://doi.org/10.1093/sleep/23.1.1f
- ↑ Markus Dworak, Alfred Wiater, Dirk Alfer, Egon Stephan, Wildor Hollmann, Heiko K. Strüder (March 2008). Increased slow wave sleep and reduced stage 2 sleep in children depending on exercise intensity. Sleep Medicine, Volume 9, Issue 3, March 2008, Pages 266-272, https://doi.org/10.1016/j.sleep.2007.04.017
- ↑ Barratt, E. S., Beaver, W., & White, R. (1974). The effects of marijuana on human sleep patterns. Biological Psychiatry, 8(1), 47–54.
- ↑ Irshaad O. Ebrahim, Colin M. Shapiro, Adrian J. Williams, Peter B. Fenwick (January 2013). Alcohol and Sleep I: Effects on Normal Sleep. Alcoholism: Clinical & Experimental Research, Volume 37, Issue 4, April 2013, Pages 539-708, https://doi.org/10.1111/acer.12006
- ↑ polyphasic.net. Retrieved 07-12-2020.
- ↑ Mathias Berger, Dieter Riemann (December 1993). REM sleep in depression—an overview. Journal of Sleep Research, Volume 2, Issue 4, December 1993, Pages 211-223, https://doi.org/10.1111/j.1365-2869.1993.tb00092.x
- ↑ J. De Koninck, D. Lorrain, G. Christ, G. Proulx, D.Coulombe (September 1989). Intensive language learning and increases in rapid eye movement sleep: evidence of a performance factor. International Journal of Psychophysiology, Volume 8, Issue 1, September 1989, Pages 43-47, https://doi.org/10.1016/0167-8760(89)90018-4
- ↑ J. M. Siegel (November 2001). The REM sleep-memory consolidation hypothesis. doi:10.1126/science.1063049
