Don’t forget to set your clocks ahead one hour.Daylight saving time begins this Sunday, with a common recommendation to set your clocks ahead one hour before going to sleep Saturday night. Setting clocks ahead means most people will lose one hour of sleep. In exchange, there will be an extra hour of daylight in the evenings.“That glorious after-work sunshine comes at a price – a horrible groggy feeling on Monday morning,” said Dr. Raghu Upender, medical director of the Vanderbilt Sleep Disorders Center.Most people only need a day or two to adjust to the time shift, Dr. Upender says, but some can take as long as a week.