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Sleep–Wake Disorders
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Margaret Kay-Stacey, Eunice Torres-Rivera, Phyllis C. Zee
A typical night in an adult or adolescent begins with 90–110 minutes of NREM sleep followed by a brief, several-minute REM period and then cycling between REM and NREM every 90–120 minutes. There is a rapid descent from stage N1 to stage N2. After 10–25 minutes of N2, there may be deepening into stage N3, slow-wave sleep, for a number of minutes, particularly during the first third of the night in younger subjects. A complete night usually contains four or five sleep cycles. Slow-wave sleep tends to occur during the first third of the night, and REM period duration tends to lengthen as the night progresses (Figure 28.6).
What are dreams, and how do we study them?
Published in Josie Malinowski, The Psychology of Dreaming, 2020
For the average person, non-REM sleep dominates the first half of the night, with REM sleep periods much more frequent and much longer in the second half of the night. A sleep cycle, which takes us through the non-REM stages and then into REM, lasts for about 90 minutes, so if you slept for seven and a half hours, you would have gone through five sleep cycles.
What Actually Is Sleep?
Published in Zippi Dolev, Mordechai Zalesch, Judy Kupferman, Sleep and Women's Health, 2019
Zippi Dolev, Mordechai Zalesch, Judy Kupferman
Each night comprises an average of 4–6 sleep cycles, with each cycle lasting 90–110 minutes. Each cycle has a segment of NREM sleep followed by a REM segment. The duration of REM sleep increases in each cycle toward morning, whereas the duration of NREM decreases.
Sleep is something, not nothing: an interprofessional approach to sleep assessment and treatment to support substance use recovery
Published in Journal of Social Work Practice in the Addictions, 2023
Jennifer Gardner, Margaret Swarbrick, Robert H. Kitzinger
Other basic sleep definitions that are of importance to this topic include circadian rhythm, rapid eye movement (REM) vs. non-rapid eye movement (non-REM) sleep and sleep onset latency. Circadian rhythm is defined as the physiological 24-hr time pattern of human life, which includes periods of consciousness/alertness and sleep. This pattern is established early in life through consistent patterning of waking/sleeping, therefore is contextual in nature (Meadows et al., 2017). Sleep progresses through predictable stages of non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, with the majority of sleep as NREM. Although REM constitutes less time during a sleep cycle, it does involve high brain activity and is associated with restoration. Sleep onset latency is in essence the ‘time from turning off the light to falling asleep,’ or the time it takes to fall asleep from consciousness. These terms will be important to understand to guide professionals when engaging in assessment and intervention.
Diurnal variations in multi-sensor wearable-derived sleep characteristics in morning- and evening-type shift workers under naturalistic conditions
Published in Chronobiology International, 2021
Ian Clark, Benjamin Stucky, Yasmine Azza, Patrick Schwab, Stefan Müller, Daniel Weibel, Daniel Button, Walter Karlen, Erich Seifritz, Birgit Kleim, Hans-Peter Landolt
When bedrest occurs on the ascending slope of the core body temperature rhythm, then sleep propensity is low and sleep continuity is severely disrupted (Dijk and Czeisler 1994). We captured the proportion of REM sleep during the first NREM-REM sleep cycle and latencies to the first REM sleep episode to estimate the timing of REM sleep that is coupled tightly to the core body temperature rhythm (Czeisler et al. 1980b). The REM% approximated a diurnal oscillatory pattern, such that proportions were highest between 08:00 and 10:00 and lowest between 18:00 and 22:00. Sleep propensity and sleep duration were lowest and WASO percentage was highest on the descending slope of the REM% curve in our sample. The maximum of WASO in MT displayed a large confidence interval, i.e., it occurred between 07:19 and 15:40 and could only be estimated with rather high uncertainty. Latencies to REM sleep onset were shortest during morning hours of 06:00 to 08:00 and longest during the evening and nighttime hours of 20:00 to 22:00. Taken together, the curves of sleep characteristics show the expected approximate diurnal timing based on reports in the literature under imposed ultradian activity-bedrest and strictly controlled conditions (Czeisler et al. 1980b; Gonnissen et al. 2013).
Does lunar cycle affect biological parameters in young healthy men?
Published in Chronobiology International, 2021
Ismail Dergaa, Mohamed Romdhani, Mohamed Saifeddin Fessi, Helmi Ben Saad, Amit Varma, Ali Ben Salem, Brijeshkumar Gadhavi, Mokhtar Chaabane, Nizar Souissi, Omar Hammouda
During the baseline week preceding the study, participants were instructed to maintain their sleep-cycle within a self-selected range of 8 h of nocturnal sleep, from 22:00 to 06:00 h as suggested times. In the morning testing sessions, participants were awoken after 8 h in bed. They were then advised to take 30 min of rest in a comfortable armchair following which fasting blood samples were collected. In the evening testing sessions, participants were awoken in the morning at 06:00 h, after 8 h in bed, having had a standardized iso-caloric breakfast 30 min after waking up that morning. They stayed awake until mid-day doing the advocated consistent passive activities as in previous nights. During this time, they were not allowed to consume food, but were allowed to consume alkaline water. At mid-day, participants had a standardized iso-caloric lunch after which they were advised to perform passive activities until 18:30 h. Thereafter they had 30 min of rest-time sitting on comfortable armchairs followed by the blood test collection. The participants were asked to abstain from caffeine and alcohol consumption before and during the experimental sessions.