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Overview Is there a sufficient evidence base for the U.S. Department of Health and Human Services (DHHS) to develop a comprehensive set of physical activity guidelines for Americans? To address this question, the Food and Nutrition Board and the Board on Population Health and Public Health Practice, both of the Institute of Medicine (IOM), collaboratively planned the Workshop on the Adequacy of Evidence for Physical Activity Guidelines Development. The workshop, which was sponsored by DHHS, was held in Washington, DC, on October 23â24, 2006. Thirty expert research scientists and physical activity practitioners from government and academia gave formal presentations during the workshop. The invited workshop moderators, speakers, and discussants were asked to consider the available evidence related to physical activity and the general population, as well as special population subgroups including children and adolescents, pregnant and postpartum women, older adults, and persons with disabilities. Additionally, presenters were asked to consider specific issues of relevance in assessing the quality and breadth of the available evidence. However, presenters were asked not to conduct a systematic review of the evidence for a particular population or topic, and they were advised not to propose physical activity guidelines at the workshop. ____________________________________ The planning committeeâs role was limited to planning the workshop, and the workshop summary has been prepared by the workshop rapporteurs as a factual summary of what occurred at the workshop. 1
2 PHYSICAL ACTIVITY WORKSHOP THE WORKSHOP The chair of the planning group, Dr. William L. Haskell, served as the overall moderator for the workshop. He was assisted by seven col- leagues who moderated the presentations and discussions for six plenary sessions. After an overview of the purpose and structure of the work- shop, expert panels addressed the amount and strength of the evidence relating physical activity to health promotion and chronic disease preven- tion, obesity and weight management, and risks of harm. Later in the program, special consideration was given to children and youth, pregnant and postpartum women, older adults, and persons with disabilities and chronic health conditions. Periodically, scheduled discussants provided supplementary information on each major topic. During each group dis- cussion, members of the audience provided additional evidence, raised questions, and suggested additional points for consideration by DHHS. At the end of the workshop, moderators summarized the evidence related to the major topics covered and identified a number of issues that would need to be considered if DHHS decides to develop evidence-informed physical activity guidelines for Americans. This report is a summary of the workshop presentations and discussions. Appendix A provides the workshop agenda, Appendix B contains the biographical sketches of the presenters, and Appendix C lists the workshop participants. For convenience, Appendix D identifies acronyms and abbreviations, and Appendix E provides a glossary of selected terms. The transcripts and slides used during presentations served as the basis for the summary, but some of the content has been rearranged for greater clarity. None of the statements made in this workshop summary represents conclusions, recommendations, or group consensus. Two terms used throughout the summary merit special attention. Physical activity refers to body movement that is produced by the contraction of skeletal muscle and that substantially increases energy expenditure. Exercise often refers to planned, structured, and repetitive body movement to improve or maintain one or more components of physical fitness. In some cases, these two terms are used interchangeably. As indicated in Chapter 8, which covers the closing session, a sizable body of literature was identified that documents a wide variety of benefits of physical activity for all the population groups examined. For each outcome, the strength of the evidence and the amount of evidence varies depending on the topic. Overall, the body of evidence includes
3 OVERVIEW large and small randomized controlled trials, meta-analyses and systematic reviews, prospective observational studies, consecutive case series, caseâcontrol studies, genetic studies, and studies of biological mechanisms. In addition, considerable evidence addresses the risks associated with physical activity, ways to reduce the risks, and considerations in weighing the risks against the benefits. Although the final chapter summarizes information from the closing session on the amount and strength of the available evidence, this information does not represent conclusions or recommendations at this workshop.
