Sleep extension: An explanation for increased pandemic dream recall?

Abstract

The Coronavirus Disease 2019 (COVID-19) pandemic has dramatically impacted the lifestyle of individuals across the globe. In many countries, nationally instituted shelter-in-place orders and closures of non-essential businesses have left many without employment and have forced others to work from home. These policy shifts have changed or removed the socially- and occupationally imposed demands that typically influence sleep schedules. Lifestyle and schedule changes that have stemmed from the COVID-19 pandemic have not gone unnoticed to those in the sleep research and sleep medicine communities. Several recently published and ongoing studies have aimed to track sleep and sleep-related behaviors during these unprecedented times. Initial reports suggest that sleep duration and quality changed during the early phases of the pandemic. For instance, multiple studies found increased sleep duration [1, 2] and time in bed [2, 3] in populations under varying degrees of lockdown (e.g. in the United States and in four European countries). However, unexpectedly, the same studies found a decrease in self-reported sleep quality [1, 3]. To explain these paradoxical findings, the authors proposed that increased stress from life changes (e.g. loss of employment, financial hardship, or new childcare demands) or increased psychological health issues (e.g. anxiety, loneliness) may have negatively impacted sleep quality despite increased total sleep time. In parallel, anecdotal evidence has surfaced that individuals are remembering more dreams and that dream content has become more vivid during the pandemic. Such reports have been covered by a number of major news outlets, including the New York Times, Time magazine, Smithsonian magazine, and National Geographic magazine. Many have turned to the dream simulation theory, which posits dreams provide a chance to “work out” future or current threatening or social scenarios [4], to explain why dream frequency and content are changing. However, we are not aware of any empirical work that has explored or confirmed this hypothesis. We posit that the three phenomena described above-longer sleep, more fragmented sleep, and frequent/vivid dream recall-are not coincidental. Instead, these sleep behaviors might all be caused by naturalistic “sleep extension,” which is defined as the act of extending one's sleep duration beyond habitual levels [5]. Sleep extension has been used as a research tool for decades, and, more recently, has been implemented in both controlled and applied research settings as a means to “bank” sleep [6]. Studies on sleep extension have provided unique insight into the nature of reducing “sleep debt” and the limits of the sleep homeostat. That is, they hint at what might happen when an individual has unrestricted time for sleep over an extended period of time-something akin to what might be the case for some individuals during the COVID-19 pandemic.