A new U.S. study finds that exercise can help reduce anxiety and depression, even when you don't feel like working out.
Researchers at the University of Colorado Boulder found that being forced to exercise -- for instance by a doctor or gym instructor -- helps reduce stress, anxiety and depression just as well as exercising voluntarily does.
Past studies have already shown that people who exercise are more protected against stress-related disorders, but scientists wanted to see if the benefits remain after the perception of control is removed from the equation.
To reach their findings, lead researcher Benjamin Greenwood, an assistant research professor in the university's Department of Integrative Physiology, and his team designed a lab experiment using rats. During a six-week period, some rats remained sedentary, while others exercised by running on a wheel.
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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 mechanized wheels that rotated according to a predetermined schedule. For the study, the motorized 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. 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.