Not getting enough sleep does more than make you tired, it also raises your risk of developing life threatening illnesses.
A study at Boston's Brigham and Women's Hospital finds people who get fewer than five hours of sleep a night have an increased risk of Type II diabetes.
When you sleep also plays a role.
Volunteers in the study slept at varying times of the day and night.
That knocked their body's master biological clock out of whack and caused their metabolic rate to slow down by eight-percent.
The study appears in the journal Science Translational Medicine.