researcher Shawn Youngstedt is about to embark on a round of
illuminating research expected to spotlight the importance of sunshine
in our lives.
Dr. Youngstedt, an
assistant professor at the Department of Exercise Science, Arnold School
of Public Health, is testing whether exposure to bright light will
reduce the stress levels of people with high levels of anxiety.
“Bright light has been used to treat depression for some
time,” said Youngstedt, an expert
on sleep, circadian
rhythms and the influence of exercise and bright light on mental health.
and anxiety are similar biochemically and people tend to have both,” he
said. “Whereas anxiety and depression are the most common mental
disorders, much more research has been done on depression than on
Using light to treat
depression has gained acceptance in parts of the world where the climate
severely limits exposure to sunlight. In Scandinavia, for example,
patrons can even take their coffee and croissants beneath light boxes at
light cafes (luskafe).
But even in
subtropical South Carolina, exposure to natural sunlight is no
guarantee. “On the whole, people don’t get enough sunlight. Even in
very sunny areas of the country the average person is outside less than
an hour per day,” Youngstedt said.
light/anxiety treatment project will take most of a year to complete. It
is supported by a $25,000 grant from the Litebook Company Ltd., a
manufacturer of therapeutic lights based in Medicine Hat, Alberta,
The first part of the
research involves identifying a sample of about 30 people, ages 18-30,
with high levels of anxiety. Youngstedt will ask for volunteers from
campus locations such as the USC Counseling and Human Development
Center. Newspaper ads are another possible recruiting tool.
Applicants will fill
out a comprehensive questionnaire followed by screening from a clinical
psychologist to exclude subjects who are depressed.
After screening, the
subjects will be assigned either to bright light treatment or negative
ion treatment, another therapy that has been used for depression and
The negative ion
generator is a small metal box with a web of wire filaments jutting from
the top. The device produces negatively charged air molecules that,
when inhaled, are believed to produce mood enhancing biochemical
The light box used in
the test is about the size of a laptop computer and produces a light
intensity of about 10,000 lux. Lux is the international measure of the
illuminating power of light.
Experts say the
average living room measures less than 100 lux, while bright office
lighting is between 300 to 500 lux. A cloudy day can measure between
1,000 to 5,000 lux. Youngstedt says 10,000 lux is “equivalent to being
outside on a sunny day looking at the horizon.”
The volunteers will
be introduced to the light or negative ion treatment during a 45 minute
initial session at Youngstedt’s lab. Following the test, the subjects
will fill out a questionnaire reporting on their moods. Blood pressure,
an excellent physiological index of anxiety, will be taken before and
after the session.
From the lab, the
testing moves to the subjects’ homes for a four-week period in which,
within 15 minutes of awakening, they will be exposed to daily 45-minute
sessions with either the light box or the negative ion generator.
At the end of each
week, a researcher will visit with a questionnaire and take a blood
psychologist will be on call during the treatment period. He and other
staffers will be on the alert for side effects that may arise such as
headaches or eye soreness.
At the end of the
test the clinical psychologist will review the treatment with the
Youngstedt says the
whole project will probably take about a year to finish before he’s
ready to write and publish a report.
• If you are interested in volunteering for this study, please contact
Dr. Youngstedt at 803-777-9929 or e-mail him at