Sleep is crucial to maintain a healthy lifestyle. Although the standard recommendation of 7- 8 hours of continuous sleep is familiar, alternative sleep patterns, including a biphasic pattern, may provide further insights into patient care. Interestingly, history shows that biphasic sleep patterns may not be as uncommon as we think.
Although the standard recommendation of 7- 8 hours of continuous sleep is familiar, alternative sleep patterns, including a biphasic pattern, may provide further insights into patient care.The Non-REM sleep cycle consists of three stages. Stage 1 accounts for 5% of total sleep and is the stage of sleep between wakefulness and sleep, sometimes referred to as the drowsy state.1 During this stage, there is a transition from beta and gamma brain waves to alpha and eventually theta waves. Stage 2, which accounts for 45%-55% of total sleep, is the first unequivocal stage of the sleep cycle during which muscle activity decreases and awareness of the outside world begins to fade. Eye movements stop and brain waves become slower with occasional bursts of rapid waves called sleep spindles.1,2 Brain waves during stage 2 are primarily theta waves. Stage 3 accounts for 15%-20% of total sleep and is primarily characterized by delta brain waves along with a few sleep spindles.1 During this stage in the sleep cycle, physical indicators such as brain temperature, breathing rate, heart rate, and blood pressure are all at the lowest.1,2 REM sleep accounts for up to 20-25% of total sleep time in adult humans.1 Brain activity during REM sleep is characterized by low-amplitude, mixed-frequency brain waves including theta waves, alpha waves, and beta waves.1 During the REM sleep cycle, blood pressure rises and breathing is more rapid, irregular, and shallow.2
Now let’s look at the effects of alternative sleep patterns compared to the standard monophasic sleep patterns among different cultures. One study assessed sleep architecture of consolidated and split sleep due to the dawn (Fajr) prayer among Muslims and its impact on daytime sleepiness. The participants spent three nights in the Sleep Disorders Center and received an adaptation night, a consolidated sleep night, and a split-sleep night.3 In the consolidated sleep protocol, participants slept seven and a half consecutive hours overnight. In the split-sleep protocol, they slept for four hours, were awake for 45 minutes, and slept for an additional three and a half hours.3 Polysomnography and multiple sleep latency tests were used to assess the daytime sleepiness of the participants. The results found there were no differences in sleep architecture or daytime sleepiness between the protocols.3
Another study assessed sleep patterns and quality in Omani adults. For this study, two thousand questionnaires were randomly distributes among Omani adults aged 18-65 years.4 Five hundred subjects fulfilled the inclusion criteria and were categorized into age groups. In addition to demographic data and sleep habits, sleep quality, and daytime sleepiness were assessed using the Pittsburgh Sleep Quality Index and the Epworth Sleep Scare respectively.4 The results of the study found that the primary sleep patterns among the Omani were either polyphasic, having more than two sleep periods per day, or biphasic, having two sleep periods.4 Monophasic and biphasic patterns were associated with moderate daytime sleepiness and polyphasic patterns were associated with severe daytime sleepiness.4
Yet another study evaluated the sleep patterns of cloistered monks and nuns, who adhere to a 10-century-old strict schedule with a common zeitgeber of a night split by a 2-to-3-hour long Office (Matins).5 To observe the patterns, five monks and five nuns followed the split-sleep (biphasic) schedule for 5 to 46 years and 10 controls underwent interviews, sleep scales, and physical examination and produced a week-long sleep diary and actigraphy, plus 48-hour recording of core body temperature.5 The results of the study found that monks and nuns had an earlier sleep onset and offset, shorter sleep time, and more frequent hyponagogic (transition between sleep and wakefulness) hallucinations compared to the controls. The biphasic temperature profile in monks and nuns suggests the human clock adapts to and even anticipates nocturnal awakenings.
Evidence suggests that biphasic sleep patterns have been practiced for centuries; however, there is limited research on the long-term effects of biphasic sleep compared to monophasic sleep. While limited, this evidence and the historical use of alternative sleeping patterns may be informative for integrative practitioners. When a patient notes that he or she awakes in the middle of the night, we may instead explore the healthfulness for this individual rather than using tools to override what may be their natural or behavior-derived pattern. The art of practice extends to exploration of these novel and alternative concepts in addition to standard recommendations.
- Association AS. What is Sleep? 2016; accessed http://www.sleepassociation.org/patients-general-public/what-is-sleep/
- Bahammam AS et al. Annals of Thoracic Medicine. Jan 2012;7(1):36-41.
- Juma I. Sleep Medicine. Dec 2015;16, Supplement 1:S33. doi: http://dx.doi.org/10.1016/j.sleep.2015.02.081
- Arnulf I et al. Chronobiology International. Dec 2011;28(10):930-941.