The Effects of Night Shift Work on Health Across the Menstrual Cycle

Modern society demands around-the-clock services, with an estimated 20% of workers involved in night shifts. Shift work disrupts the circadian rhythm and has been linked to increased risks of obesity, metabolic syndrome, glucose dysregulation, and immune system issues. Sleep deprivation, especially during wakeful nights, is associated with elevated levels of central nervous system biomarkers like Tau and Amyloid-β proteins, which are implicated in brain disorders such as Alzheimer's disease. However, the effects of sleep deprivation on women, particularly in relation to hormonal fluctuations during the menstrual cycle, remain largely unexplored. The menstrual cycle, which occurs in cis-women of childbearing age, involves significant fluctuations in estrogen, a hormone known for its neuroprotective properties. Estrogen impacts memory, executive function, and may play a role in protecting against neurodegenerative conditions like Alzheimer's disease. Previous studies have largely focused on men or women using hormonal contraceptives, leaving a gap in understanding how natural hormonal cycles impact the response to sleep deprivation. This study addresses this gap by focusing on healthy young women with regular menstrual cycles who do not use hormonal contraceptives. Participants will undergo an adaptation night followed by a sleep condition and a wake condition experiment. The goal is to better understand how hormonal changes throughout the menstrual cycle influence the body's response to sleep deprivation and stress, particularly in areas such as metabolism, brain function, and immune, system, and microbiota.