Background: Coronavirus disease 2019 (COVID-19) seriously affected the whole of Italy. The extreme virulence and the speed of propagation resulted in restrictions and home confinement. This change was immediately perceived by people who found themselves exposed to feelings of uncertainty, fear, anger, stress, and a drastic change in the diurnal but above all nocturnal lifestyle. For these reasons, we aimed to study the quality of sleep and its connection to distress levels and to evaluate how lifestyle changed in the Italian population during the lockdown. Methods: By means of an Internet survey we recruited 6,519 adults during the whole of the COVID-19 lockdown (from March 10\u20131st phase to May 4\u20132nd phase). We investigated the soc...