Walking behaviours from the 1965–2003 American Heritage Time Use Study (AHTUS)

This is a secondary data analysis of an existing amalgamated data set. Noting source survey-specific limitations in comparability of design, we determined age-standardized participation (and associated durations) in any walking, walking for exercise, walking for transport, walking the dog, sports/exercise (excluding walking), and all physical activity for those survey years for which sufficient relevant data details were available.Data processing revealed inconsistencies in instrument administration, coding various types of walking and in prompting other sport/exercise across surveys. Thus for the entire period, application of inferential statistics to determine trend for a range of walking behaviours could not be done with confidence. Focusing on the two most comparable survey years, 1985 and 2003, it appears that walking for exercise in America has increased in popularity on any given day (from 2.9 to 5.4% of adults) and accumulated duration amongst those who walk for exercise (from 30 to 45 mins/day). Dog walking has decreased in popularity over the same time period (from 9.4 to 2.6%). Associated duration amongst dog walkers was stable at 30 mins/day.The noted and sometimes substantial differences in methods between the various survey administrations preclude stringent interpretation of these trends in walking behaviours and the use of conventional application of inferential statistics to evaluate significance of time trends. Although the AHTUS offers the most comprehensive attempt at harmonization yet undertaken with these individual time-use surveys, we found that any noted cross-time changes in walking and physical activity behaviour are not easily interpreted in terms of conventional epidemiological approaches and could be true changes, artefact related to instrument and method changes, or both. Public health utilization of the AHTUS, could be enhanced with greater attention to methodological issues known to influence estimation of physical activity behaviour