Human sleep in COVID-19 pandemic times

In the 2020–2022 biennium, humankind faced one of the worst public health crises of all time. The SARS-CoV-2 spread posed unprecedented challenges to modern societies, pervasively reshaping the everyday life of the world population. In this Thesis, we addressed how the multifaced lifestyle and societal changes due to the COVID-19 outbreak interacted with human sleep, describing a series of studies aimed at unraveling the brief- and long-term consequences of the pandemic period on sleep features of the Italian population. The project consisted of a cross-sectional investigation engaging almost fourteen thousand participants during the first lockdown and three longitudinal assessments involving over two thousand respondents across different pandemic stages (the final weeks of lockdown, the second contagion wave period, and the emergency resolution two years later). We examined the progression of sleep ad mental health, outlining possible demographic, psychological, and behavioral risk factors during different emergency phases. We addressed the transient changes in sleep duration and sleep schedules, the consequences of working adjustments, and how all these events interacted with the different circadian typologies. We also explored the repercussions of the increased digital screen time under social distancing, and the role of sleep on the subsequent risk for long COVID symptoms. Finally, we contextualized the project results in the international framework, providing an updated and comprehensive overview of the scientific evidence in the field and discussing the learned lessons from the pandemic to better manage the complex and inextricable relationship between sleep and social/behavioral factors.