Automated telephone calls may be able to promote behavior change among adults who are not meeting the recommended level of 30 minutes of moderate-intensity exercise on most days, according to a new study.

Researchers found that participants who received an automated, computer-based telephone intervention were more likely than a comparison group to increase their level of physical activity after three months. The telephone approach had lost effectiveness by the time researchers conducted a six-month follow-up, however.

Lead researcher Bernardine M. Pinto, Ph.D., called the study, which was published in the August 2002 issue of the American Journal of Preventive Medicine, "the first -- to use telephone delivery of a computerized 'simulation' of physical activity counseling."

The study examined 298 randomly selected participants who were sedentary and had unhealthy diets (for example, high in fat and processed foods). Half of the group received an automated telephone intervention focused on enhancing motivation to engage in moderate-intensity physical activity, such as walking. The other half, a comparison group, received an intervention designed to boost motivation to improve eating habits.

"Like telephone counseling offered by human counselors, we expected that [the system] would overcome problems with scheduling and attending to face-to-face meetings," says Pinto. "Unlike human counselors, [the system] would be accessible at any time and less likely to be perceived as judgmental."

She notes that telephone interventions have been successful in promoting improved health behaviors, including increased physical activity, in a range of populations. In Pinto's study, most participants (72 percent) were women; 45 percent were white, and 45 percent were African American.

Participants called a number and reached a computerized program, which used synthesized speech to ask questions about current activity levels and readiness to change behavior. The computer also relayed comments on participants' responses. Subjects provided answers using their telephone keypads. The computer program assessed the participants' motivation, counseled them on their physical activity or eating behaviors, and offered a task or goal designed to promote or sustain positive behavior changes. Participants and their primary care physicians received computer-generated monthly reports documenting their level of physical activity.

After three months, 26 percent of the participants receiving the physical activity intervention had achieved the recommended levels of exercise, compared to 19.6 percent of the comparison group. The groups did not differ significantly at six-month follow up.

The researchers found no relationship between the outcome and the number of times participants called the system. They noted that one-third of the participants in the physical activity group did not use the system at all and the number of users in both groups steadily declined over the course of the study.

The researchers speculate that participation dropped off as the intervention's novelty wore off. In addition, some participants noted that they preferred human intervention or would have appreciated reminder calls.

"We relied on the users to actively initiate all contacts to access the intervention," writes Pinto. "Placing this responsibility on them may have compromised our ability to deliver the intervention." She notes that the current version of the intervention automatically calls participants according to a set schedule.

Despite the drop-off at the six-month mark, Pinto emphasizes that the intervention's short-term effects are nevertheless promising and suggests continued refinement of automated telephone interventions.

The study was funded in part by the National Heart, Lung and Blood Institute and the Harvard Pilgrim Health Care Foundation.

---The Health Behavior News Service

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