She also said the findings may apply to people who work early morning shifts since they have to get up during the night. (scientificamerican.com)
Papa Natural and I took turns doing early morning shifts for years. (mamanatural.com)
Basically any moving parts will start to rattle or screetch, the back doors wont close right unless you SLAM them, which is bad if you have a night job or early morning shift where all your neighbors are sleeping. (edmunds.com)