Your body's circadian rhythms are attuned into sunrise and sunset, so don't be surprised if you're groggy despite going to bed earlier.
If "fall back" means an extra hour of sleep, why do I still feel groggy?
Daylight is the primary regulator of our body's circadian rhythms -- and Daylight Saving Time ends Sunday. It means earlier sunrises and sunsets. But what does it mean for a person's sleep schedule?
"You're basically changing time zones," said Dr. Vishesh Kapur of the UW Medicine Sleep Center. "Being in a different time zone than your biological clock than your body is in is bad for your body. It may affect your body in ways besides how alert you feel. Your internal clock has to start to match the new times. Usually it will take two or three days for your clock to adjust."