So you want to ward off the blues? Exercise!
Sure, some critics will argue, most of the evidence linking exercise with
depression prevention comes from cross-sectional studies, so that it's
possible that exercise does not prevent depression, but rather that upbeat
people are more likely to exercise in the first place. But now a new study,
with a large number of subjects and a prospective design, has also linked
exercise with less
depression.FIG1
The study was posted October 8, 2008, in the Journal of Psychiatric
Research.
Its results bolster the argument that exercise can prevent depression,
Xuemei Sui, M.D., a research associate at the University of South Carolina and
the lead investigator, believes. "Improving one's fitness can not only
lower many disease risks such as cardiovascular disease and certain types of
cancer,... but also benefit one's mental well-being," she asserted.
Ronald Kamm, M.D., a sport psychiatrist in Oakhurst, N.J., and a past
president of the International Society for Sport Psychiatry, concurs with Sui."
This is a good study," he said. "It adds to the literature
showing a preventive effect of exercise regarding depression."
The study, which started in 1970, involved more than 14,000 men and women
enrolled in the Aerobics Center Longitudinal Study in Dallas. None of the
subjects had a history of mental illness, cardiovascular disease, or cancer.
Their cardiorespiratory fitness was measured at the start of the study with a
maximum treadmill exercise test. They were evaluated for depression one or two
times during the follow-up period, which ranged from one to 15 years, with the
average being 12 years. At the end of that time, 1,022 subjects reported
having had depressive symptoms at the time of either or both assessments.
The researchers found that subjects who had been more fit at the start of
the study were significantly less likely to experience depression during the
follow-up period than were subjects who had been less fit at that time.
Further, the results held even when a number of possibly confounding
factors—baseline physical examination year, depression survey year,
smoking status, alcohol consumption, body mass index, high blood pressure, and
diabetes—were considered. And perhaps most strikingly, there appeared to
be a dose-response relationship between fitness and the prevention of
depression.
"I'm also glad that the researchers talked about the
obesity-depression link [in their report], as psychiatrists need to be aware
of that," Kamm said.
Indeed, Sui and her colleagues found that obese subjects had a
significantly higher risk of depressive symptoms than nonobese subjects, and
in a previous study, that overweight or obese postmenopausal women could
improve their physical fitness with as little as 72 minutes of moderately
intense physical exercise a week.
An abstract of "Prospective Study of Cardiorespiratory Fitness
and Depressive Symptoms in Women and Men" can be accessed at<www.sciencedirect.com>
by clicking on "J" under "Browse by Title," then"
Journal of Psychiatric Research," then "Articles in
Press." ▪