Counseling generally encourages exercise, according to Dr. Melvyn Hillsdon of University College London and colleagues. However, the researchers found no evidence that counseling can help people reach a specific exercise goal.
"More research is needed to establish which methods of exercise promotion work best in the long term to encourage different types of people to be more physically active," Hillsdon says, noting that most of the studies included in the review lasted less than a year.
The review appears in the January issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
Hillsdon and colleagues reviewed 17 studies that included 6,255 healthy adults age 16 and older. All of the studies were randomized controlled trials that compared different ways to encourage sedentary adults to become more physically active.
The studies measured the effects of interventions such as individual and group counseling, telephone calls, written motivational materials and supervised and unsupervised exercise.
Hillsdon and colleagues say continuing professional support combined with self-directed exercise may provide the most consistent results, but they acknowledge the studies vary too widely to recommend any single approach.
The differences between the studies also made it difficult to "determine if any type of physical activity is more likely to be adopted than any other type of physical activity," Hillsdon says.
Most of the studies "were not designed to examine this question and as such generally did not report exactly what type of physical activity was performed," he explains.
The researchers found no evidence that exercise-related heart problems or injuries increased among the study participants.
Hillsdon says the studies included in the review suffer from some biases. For instance, many of the studies failed to consider how a person's current activity levels may have influenced their reaction to exercise counseling.
Many of the studies also offered options such as supervised exercise programs that "would be difficult to deliver in usual practice, as they would demand large resources," Hillsdon says.
Another review of recent studies published in the American Journal of Health Promotion2 suggests certain policy and environmental changes can encourage physical activity as well.
Small changes such as workplace signs that encourage employees to use the stairs and larger interventions that provide more places in the community to exercise can encourage physical activity, according to Dr. Dyann Matson-Koffman of the National Center for Chronic Disease Prevention and Health Promotion and colleagues.
For the most part, the studies reviewed by Matson-Koffman and colleagues were not as rigorous as the randomized controlled trials included in the Cochrane analysis.
The Centers for Disease Control and Prevention recommend that adults participate in "moderate-intensity" exercise – walking briskly, dancing, swimming or bicycling – for 30 minutes a day at least five days a week. According to a 2001 CDC report, more than 70 percent of Americans do not exercise enough to meet this standard.
The new Dietary Guidelines released this month by the Department of Health and Human Services and the Department of Agriculture recommend at least 60 to 90 minutes of moderate intensity exercise to maintain weight loss.
FOR MORE INFORMATION
Health Behavior News Service: (202) 387-2829 or www.hbns.org.
Interviews: Contact Melvyn Hillsdon at +44 020 7679 1713 or m.hillsdon@public-health.ucl.ac.uk;
Dyann Matson-Koffman at (770) 488-8002. or: dmatsonkoffman@cdc.gov.
1 Hillsdon et al. Interventions for promoting physical activity. The Cochrane Database of Systematic Reviews 2005, Issue 1 The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.
2 Matson-Koffman et al. A Site Specific Literature Review of Policy and Environmental Interventions that Promote Physical Activity and Nutrition for Cardiovascualr Health: What Works. The American Journal of Health Promotion, January/February 2005. Vol 19. No. 3. Visit www.healthpromotionjournal.com or call 248-682-0707.