Previously studies have shown that people who exercise are
more protected against stress-related disorders, and scientists know that the
perception of control can benefit a person's mental health. But it has been an
open question whether a person who feels forced to exercise, eliminating the
perception of control, would still reap the anxiety-fighting benefits of the
People who may feel forced to exercise could include high
school, college and professional athletes, members of the military or those who
have been prescribed an exercise regimen by their doctors, said Benjamin
Greenwood, an assistant research professor in CU-Boulder's Department of
"If exercise is forced, will it still produce mental
health benefits?" Greenwood asked. "It's obvious that forced exercise
will still produce peripheral physiological benefits. But will it produce
benefits to anxiety and depression?"
How the study was
To seek an answer to the question Greenwood and his
colleagues, including Monika Fleshner, a professor in the same department,
designed a lab experiment using rats. During a six-week period, some rats
remained sedentary, while others exercised by running on a wheel.
The rats that exercised were divided into two groups that
ran a roughly equal amount of time. One group ran whenever it chose to, while
the other group ran on mechanised wheels that rotated according to a
predetermined schedule. For the study, the motorised wheels turned on at speeds
and for periods of time that mimicked the average pattern of exercise chosen by
the rats that voluntarily exercised.
After six weeks, the rats were exposed to a laboratory
stressor before testing their anxiety levels the following day. The anxiety was
quantified by measuring how long the rats froze, a phenomenon similar to a deer
in the headlights, when they were put in an environment they had been
conditioned to fear. The longer the freezing time, the greater the residual
anxiety from being stressed the previous day. For comparison, some rats were
also tested for anxiety without being stressed the day before.
"Regardless of whether the rats chose to run or were
forced to run they were protected against stress and anxiety," said
Greenwood, lead author of the study appearing in the European Journal of
Neuroscience in February. The sedentary rats froze for longer periods of time than
any of the active rats.
"The implications are that humans who perceive exercise
as being forced — perhaps including those who feel like they have to exercise
for health reasons — are maybe still going to get the benefits in terms of
reducing anxiety and depression," he said.