Data from: Biological sex differences in sleep of male and female c57bl/6 mice

Sleep is used as a physiological outcome in research, however, few studies
have disaggregated sleep data based on sex. We investigated biological sex
differences in sleep under normal physiological conditions using male and
female C57BL/6 mice (n = 267 from 17 cohorts). Physiological parameters
were recorded for 48-hours (2 days) using non-invasive piezoelectric cages
to determine total sleep, non-rapid eye movement (NREM) sleep, rapid eye
movement (REM) sleep, and wakefulness (WAKE). To investigate sleep
differences between sexes we fit hierarchical generalized linear mixed
models with nonlinear time effects. We found substantial sex differences
in the sleep of C57BL/6 mice. Female mice slept less overall, specifically
during the dark period, with less NREM sleep compared to males. Females
also exhibited more REM sleep and WAKE. Females had shorter total and NREM
sleep bout lengths compared to males. During the light period, REM bout
lengths and WAKE bout lengths were similar between sexes; however, females
had longer REM and WAKE bouts during the dark period. Variation in all
outcomes was nominal between days and among cohorts, demonstrating rigor
and replicability of our findings. Based on these substantial sex
differences in sleep, failure to include both sexes in experimental
designs or appropriately account for sex during analysis could lead to
flawed inferences and inaccurate translational recommendations in
pre-clinical sleep studies.