TY - JOUR T1 - What they say and what they do: comparing physical activity across the USA, England and the Netherlands JF - Journal of Epidemiology and Community Health JO - J Epidemiol Community Health DO - 10.1136/jech-2017-209703 SP - jech-2017-209703 AU - Arie Kapteyn AU - James Banks AU - Mark Hamer AU - James P Smith AU - Andrew Steptoe AU - Arthur van Soest AU - Annemarie Koster AU - Saw Htay Wah Y1 - 2018/04/09 UR - http://jech.bmj.com/content/early/2018/04/09/jech-2017-209703.abstract N2 - Background Physical activity (PA) is important for maintaining health, but there are fundamental unanswered questions on how best it should be measured.Methods We measured PA in the Netherlands (n=748), the USA (n=540) and England (n=254), both by a 7 day wrist-worn accelerometer and by self-reports. The self-reports included a global self-report on PA and a report on the frequency of vigorous, moderate and mild activity.Results The self-reported data showed only minor differences across countries and across groups within countries (such as different age groups or working vs non-working respondents). The accelerometer data, however, showed large differences; the Dutch and English appeared to be much more physically active than Americans h (For instance, among respondents aged 50 years or older 38% of Americans are in the lowest activity quintile of the Dutch distribution). In addition, accelerometer data showed a sharp decline of PA with age, while no such pattern was observed in self-reports. The differences between objective measures and self-reports occurred for both types of self-reports.Conclusion It is clear that self-reports and objective measures tell vastly different stories, suggesting that across countries people use different response scales when answering questions about how physically active they are. ER -