The fourth-leading cause of death in the United States, COPD impairs airflow in the lungs. Reduced airflow means less oxygen is available to the brain, rendering people with the disease at risk for worsened mental function. Exercise tends to increase airflow in the lungs. "People with chronic lung disease may have problems with fluid intelligence-the ability to take new material and make sense of it," Emery said. "Exercise seems to help these individuals think more efficiently."

COPD and exercise

COPD is an umbrella term commonly used to refer to emphysema and chronic bronchitis. Both diseases leave patients prone to frequent upper respiratory infections, restricted airways and shortness of breath. Once considered taboo for treating COPD, said Emery, doctors now frequently recommend exercise to their patients in order to help control the symptoms of the disease. COPD is incurable; however, exercise helps increase physical endurance despite having the disease. In addition to increasing rates of respiration and blood flow, exercise stimulates the nervous system and is also associated with the release of hormones that may influence how the brain functions.

Exercise and evaluation

The researchers evaluated the effects of a single session of moderately intense exercise on 58 adults. Half of them had COPD and half were healthy. The subjects ranged in age from 56 to 85 years. Each participant was asked to ride a stationary bicycle for 20 minutes during individual exercise sessions. The resistance on the bike was increased incrementally until the subject reached peak exercise performance, determined by measuring each subject's heart rate and breathing rate throughout the session.

In a separate session, the participants were asked to watch a video on the benefits of exercise and cholesterol reduction. The researchers wanted to know what effect, if any, simply thinking and learning about exercise and health would have on the subjects. The exercise and video-viewing sessions were separated by one week.

Subjects completed an assessment of cognitive performance immediately before and after each session. The assessment evaluated aspects of mental functioning that are

In a separate session, the participants were asked to watch a video on the benefits of exercise and cholesterol reduction. The researchers wanted to know what effect, if any, simply thinking and learning about exercise and health would have on the subjects. The exercise and video-viewing sessions were separated by one week.

Subjects completed an assessment of cognitive performance immediately before and after each session. The assessment evaluated aspects of mental functioning that are thought to be responsive to exercise, such as verbal processing, attention span, short-term memory, and motor skills.

Results: verbal fluency

The COPD group showed marked improvement in one area, verbal fluency, after exercising for 20 minutes. "This indicates that they were able to process and retain information better than they could prior to exercising," Emery said. "This translates to better performance on tasks like following directions, for example." The same group showed no improvement in other areas of cognitive performance.

The healthy subjects didn't show cognitive improvement after exercising, most likely because they had healthier lungs and more physical endurance to begin with, Emery said. None of the 58 participants improved in any area of cognition after watching the video.

Previous findings

In a 1998 study, Emery found that exercise reduced anxiety and improved mental and physical endurance in people with COPD who regularly participated in aerobics and strength training sessions for 10 weeks. "The earlier study suggested that regular exercise benefits cognitive performance as well as physical endurance in patients with chronic lung disease," Emery said. "Based on these new results, we think that the effects may be apparent relatively quickly."

But don't expect to reap long-term mental benefits from just one session of exercise. Rather, the effects seem to be cumulative. "Some level of physical activity needs to be maintained in order to maintain mental benefits," Emery said. "Physical endurance decreases when a person stops exercising, and cognitive function likely follows a similar 'use it or lose it' pattern."

Emery conducted the research with Philip Diaz, an associate professor of internal medicine and member of Ohio State's Dorothy M. Davis Heart and Lung Institute; David Frid of Ohio State; and psychology graduate students Vanessa Honn and Kim Lebowitz. A grant from the National Heart, Lung, and Blood Institute supported this research.