Computer problems are giving me problems linking directly to the document. But if you go to the USDOT Time Zone docket and look at the October 27, 2005 submissions, you’ll find a submission from Dr. David Avery, Professor at the University of Washington School of Medicine. He writes:
About 10 to 20% of the people in northern latitudes in the US have either SAD or subsyndromal SAD. It is well known that the prevalence of these disorders increase with latitude. Recently, we found that those living on the western edge of Eastern Time Zone are significantly more likely to have SAD symptoms than those living on the eastern edge of the time zone. The best explanation of this finding is that the sun is rising much later on the western edge of the time zone compared to the eastern edge and those on the western edge are getting less morning light.
As I understand it, Seasonal Affective Disorder is essentially depression caused by lack of sunlight. Dr. Avery’s letter states that morning sunlight seems to be more effective at diminishing this sort of depression that sunlight during other times of the day. During part of the year, a person waking up at 6:00 a.m. Eastern Daylight Time will be getting up 2.5 hours before sunrise at 8:30 a.m.