The human body’s master clock roughly lines up with the 24-hour environmental clock, setting itself according to the body’s exposure to light and darkness. But technology has altered the intensity of light and the hours of exposure most people experience.
We are naturally attuned to the sun and the daily cycles of light and dark. Most of us are out of whack because of artificial daylight, and the impending daylight savings time isn’t going to help.
This article contains a link to a great questionnaire you can take and score yourself. It will reveal if you are a “morning,” “evening,” or “intermediate” type and then let you know exactly what time of day it would be best for you to do bright light therapy for maximum and best anti-depressant benefit.