Time Trends in Physical Activity in the Tromsų Study, Northern Norway
Although numerous studies have documented substantial health benefits of physical activity, a large proportion of the population does not met current recommendations for physical activity. To develop purposeful strategies, knowledge about physical activity trends is essential, albeit scarce. We aimed to examine secular trends in prevalence of leisure-time and occupational physical activity over the last four decades.
METHODS:
We analyzed 133 518 observations from five cross-sectional surveys between 1974 and 2008 that were part of the population-based Tromsø Study (n=37 445). Leisure time and occupational physical activity was assessed by a self-administered questionnaire. Analyses were performed for the total population and stratified by sex. Age adjustments were performed to rule out the possibility that physical activity trends could be explained by age.
RESULTS:
The percentage of sedentary men and women in leisure time remained stable at ≈20% from 1974 to 2008 and showed no sex differences. Prevalence of moderate physical activity increased from 1974 to 2000 and then started to decrease, as the prevalence of high activity increased during last decade, from 15% in 2001 to 20% in 2008. Across the whole time period, men were more likely to be highly active, whereas women were more likely to be moderately active. Prevalence of sedentary occupational activity increased gradually across the four decades, from 35% in 1979 to 53% in 2008. This trend was explained by a decrease in walking at work among women and in heavy manual labor among men.
CONCLUSIONS:
Our data from a general population show that the rate of sedentary people in leisure time has been rather stable across four last decades, whereas the rate of inactivity at work has increased steadily from 1974 to 2008. In total, people have become more sedentary during the last four decades, mainly due to more sedentary work.