Daylight saving time ends this Sunday at 2:00 a.m. It was introduced in 1918 as a way to conserve energy by making the most of summer's daylight hours. But some people say that shifting our clocks is its own form of energy drain.

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