How Sleep Is Affected by Time Changes

http://www.webmd.com/sleep-disorders/features/coping-with-time-changes

What Difference Could an Hour Make?
By Michael J. Breus, PhD
WebMD Feature

The daylight-saving time change will force most of us to spring forward and advance our clocks one hour. This effectively moves an hour of daylight from the morning to the evening, giving us those long summer nights. But waking up Monday morning may not be so easy, having lost an hour of precious sleep and perhaps driving to work in the dark with an extra jolt of java. How time changes actually affect you depends on your own personal health, sleep habits, and lifestyle.