Towards a better understanding of the ‘physical activity paradox’: the need for a research agenda
Pieter Coenen, Maaike A. Huysmans, Andreas Holtermann, Niklas Krause, Willem van Mechelen, Leon Straker, Allard J. van der Beek
Abstract
Several studies have suggested that a ‘physical activity (PA) paradox’ may exist—that is, the well documented beneficial health effects of leisure-time physical activity (LTPA) are not found for occupational physical activity (OPA). A BJSM editorial has outlined potential explanations for such a paradox.1 A recent systematic review has provided some empirical evidence that men, but not women, engaging in high (compared with low) level OPA have an 18% (95% CI 5% to 34%) increased risk of all-cause mortality.2 Nonetheless, the existence of this paradox has been questioned in a discussion paper by Professor Roy Shephard.3 Below we expand on three limitations this discussion paper raised and suggest a research agenda for generating more conclusive evidence regarding this paradox. The current evidence originated from certain regions including Scandinavia, Spain, Iran and Israel. It was suggested that this restricted geographical representation weakens the evidence. However, relatively good working conditions in western European and Scandinavian countries could attenuate the negative health effects of OPA. Studies from countries with higher work demands and/or higher environmental temperatures are likely to provide evidence for even larger negative health effects. Apart from physical work demands, other factors (eg, LTPA or socioeconomical gradients) may also vary between countries and may have an impact on the association between OPA and health. The restricted origin of evidence also raises the possibility …