Daylight saving time ends across most of the United States on the first Sunday of November, according to Time and Date, an online world clock. At 2 a.m. Sunday, Nov. 2, clocks in Florida and other states will move back by one hour, give you an extra hour of sleep that night.

Here's what you need to know about when and why the clocks change, how the switch can impact your health, and why some scientists are calling for it to be scrapped altogether

But the change is slow. Abrupt changes, flying east or west (which extends or shortens sunlight exposure, affecting melatonin), heat waves, cold snaps (raising or lowering core body temperature) or stress (which increases daytime cortisol) cause disruption in this regimen. We just haven’t evolved to cope with sudden changes.