Strong Evidence from the 2018 Physical Activity Guidelines Advisory Committee

Abstract

The U.S. Department of Health and Human Services (HHS) charged an external federal advisory committee to review the scientific literature and provide independent recommendations to the government to inform the development of the second edition of the Physical Activity Guidelines for Americans. PURPOSE: To present a selection of conclusions with evidence graded as ‘strong’ from the 2018 Physical Activity Guidelines Advisory Committee (Committee) systematic literature review. METHODS: The Committee asked 38 questions on relationships between physical activity and health outcomes in systematic literature reviews. A grading rubric was used to evaluate the strength of evidence - Strong, Moderate, Limited, or Grade Not Assignable (insufficient evidence). A grade of ‘strong’ indicated that evidence from the literature directly applied to the systematic review question; was free from serious doubts about generalizability; limited the risk of bias; showed consistency in the direction and approximate size of the effect across studies; and provided considerable confidence in the accuracy of the findings. The Committee presented its conclusions during five public meetings. RESULTS: The Committee concluded there was strong evidence that physical activity has a beneficial effect on many health outcomes, including improvements in weight and bone health in children under age six, physical function in older adults, and incidence of seven types of cancer. Examples are provided in Table 1. CONCLUSION: The Committee’s systematic reviews will be compiled into a Scientific Report and submitted to the HHS Secretary. The Department will use the Committee’s evidence-based recommendations, as well as public and federal agency comments, to develop the second edition of the Physical Activity Guidelines for Americans. The Committee’s work firmly grounds the second edition of the Physical Activity Guidelines for Americans in the current science on physical activity and health.Table 1: Selected conclusion statements for ‘strong’ evidence.