Use it or lose it, fitness experts tell us. Now a new study offers evidence that the adage really does ring true – that a lack of exercise can not only cause physical setbacks, but also psychological setbacks as well.
Researchers looked at the exercise habits of a group of older adults with chronic obstructive pulmonary disease (COPD), a lung disease that kills some 120,000 people every year in the United States. All of the participants completed a 10-week exercise rehabilitation program, then were given a home exercise program to follow on their own.
Results showed that participants achieved increased cognitive, psychological and physical function after the initial 10-week exercise intervention. But the people who stopped exercising after this period lost their gains in nearly every mental and physical characteristic that the researchers had measured.
"It's solid evidence that across-the-board declines occur when people stop exercising," said Charles Emery, the study's lead author and a professor of psychology at Ohio State University.
The study appears in a recent issue of the journal Health Psychology.
The researchers asked 28 people with COPD to first participate in a 10-week monitored exercise program. COPD, the fourth-leading cause of death in the United States, is an umbrella term for two types of lung disease – chronic bronchitis and emphysema. People with COPD usually have symptoms of both diseases.
The first five weeks of the 10-week training session consisted of daily aerobic workouts, strength training and stretching, along with weekly educational lectures on topics related to COPD. During the second five weeks, participants continued their exercise regimens at least three times each week. Participants also attended weekly stress-reduction classes throughout the 10-week session.
At the end of the 10 weeks, the researchers gave participants individualized home exercise programs to continue on their own.
A year later, the researchers contacted the participants to see if they had stayed with their exercise programs. The researchers wanted to compare a variety of psychological, cognitive and physical parameters in people who continued to work out to those who stopped exercising regularly.
Of the 28 participants, 11 (39 percent) had continued with their prescribed exercise programs during the year. The rest either said they had exercised sporadically or not at all.
At the one-year follow-up, each subject completed a number of physical, psychological and cognitive tests that they had taken at the beginning and end of the initial 10-week exercise program.
Participants provided a record of how often they had exercised during the previous year, and the type of exercise that they did during those workouts. Researchers also assessed physical endurance with a standard exercise stress test on a stationary bicycle.
The researchers measured cognitive ability with written and oral tests to assess functioning of the frontal lobe, the part of the brain associated with higher-level cognitive abilities. They used standardized tests that required participants to complete several different kinds of tasks, such as generating lists of words in specific categories, matching symbols to corresponding numbers and completing a complex connect-the-dots task.
"These cognitive tasks in our study tested a person's ability to maintain a train of thought," Emery said. "COPD-related cognitive impairment usually isn't noticeable to the untrained eye, but it can be a serious problem. Patients with COPD are often given complicated instructions for taking medications, so they need to enhance this kind of brain function as much as possible."
Participants also completed assessments of depression, anxiety and illness-related physical impairment.
All of the study participants showed gains in cognitive function, psychological function and physical endurance by the end of the initial 10-week exercise session. Participants who continued to exercise regularly during the following year maintained these benefits, although Emery noted that there were no subsequent gains in mental or physical function in this group after the first 10 weeks.
"It's possible that these exercisers would have reaped more benefits if they had increased the intensity of their workouts," he said. "Still, the fact that exercise helped them maintain function is good news."
Those who had stopped exercising regularly after the initial 10-week session showed significant declines on all mental and physical tests.
"The non-exercisers returned to their pre-study levels of cognitive, psychological and physical function," Emery said. "Some may have declined below where they originally started, as people with COPD tend to decline faster in these areas of functioning than healthy older adults."
He admits that while the declines may be more severe in people with COPD, healthy adults who stop exercising could experience similar declines to a lesser degree.
"No matter what, you've got to keep up the physical activity," he said.
Support for this study came from the National Heart, Lung and Blood Institute.
Emery conducted the study with Evana Hsiao, formerly of Ohio State; Emily Hauck, of Dean Medical Center in Madison, Wisc.; and Rebecca Shermer and Neil MacIntyre, both with Duke University Medical Center.