NL
DE
Chronic sleep restriction is widespread in industrialized societies, and an increasing number of people actively try to minimize their time spent asleep even though it is widely known that sleep fulfils vital biological functions. One sleep restriction strategy, anecdotally attributed to prolific historic individuals, is polyphasic sleep that aims to replace one extended core period of night sleep with repeated brief naps across the day.
Recently, Rosenblum et al. explored how restricting sleep to a radically polyphasic schedule affects our neural, cognitive, and endocrine activity. Now published in the journal SLEEP, the researchers describe how ten young healthy participants voluntarily restricted their sleep to one 20-minute nap every 4 hours (i.e., 6 naps per 24 hours) without any extended core sleep window, which resulted in a cumulative sleep amount of just 2 hours per day.
Even though only highly motivated and committed individuals participated in the study, few of them were able to maintain the polyphasic sleep schedule for long: only one out of the ten volunteers was able to maintain a polyphasic schedule for five weeks. After closely monitoring neural, endocrine and cognitive activity over the 24-hour cycle during polyphasic vs normal (monophasic) sleep schedules, the researchers found that adhering to a radically polyphasic sleep schedule affects vigilance and sleep physiology. Intriguingly, growth hormone secretion was almost entirely abolished during polyphasic sleep. Considering their findings, the authors conclude that it is doubtful that radically polyphasic sleep schedules can subserve the different functions of sleep to a sufficient degree.
Read the study here
Yevgenia Rosenblum, Frederik D Weber, Michael Rak, Zsófia Zavecz, Nicolas Kunath, Barbara Breitenstein, Björn Rasch, Marcel Zeising, Manfred Uhr, Axel Steiger, Martin Dresler, Sustained polyphasic sleep restriction abolishes human growth hormone release, Sleep, 2023; zsad321.
