ClockNews #10: SAD and Night-time Driving Accidents
Sunshine alternatives for those with seasonal affective disorder
As winter approaches and the days get shorter; millions of
people in the U.S. once again develop the sadness and loss of energy that is
characteristic of seasonal affective disorder (SAD). SAD is a mood disorder
related to the seasonal variations of light. As the seasons change, there is a
shift in our circadian rhythm, or our biological internal clock.
Almost every segment of our society is now working round the
clock. A report in the most recent issue of the New England Journal of Medicine
found that interns were twice as likely to have a motor vehicle accident after
working an extended shift of more than 24 hours, and more than five times as
likely to have a near-miss collision. The interns who participated in this study
also reported falling asleep while driving or while stopped in traffic.
As people get less and less sleep, their body clock, or circadian rhythm, becomes
more disrupted, and drowsy driving is the result. But the problem is more than
just getting enough sleep; when we sleep is also an important factor.
Most sleep-related accidents occur between 2 and 6 a.m., those hours when humans are biologically programmed to sleep.