MSNBC – For many Americans, the switch to daylight saving time is an annual rite of exhaustion. Gaining that extra hour of daylight at night means losing it in the morning.
The time shift disrupts the body’s natural circadian rhythm, according to sleep scientists. So the alarm clock blares just as your internal sleep-wake cycle orders you to stay snugly in bed. It’s always harder to adjust to the "spring ahead" time change (this year on March 11) than to the "fall back" change (on November 4), just as it’s harder to fly east than west.