pears to be little correlation between international levels of physical activity or inactivity and changes in life expectancy at older ages.
Steptoe and Wikman (2010) found that these measures of physical activity were significantly correlated with self-reported health for both men and women, while levels of inactivity were positively correlated with the prevalence of diabetes across countries. On the other hand, a regression analysis of the relationship between levels of physical activity and life expectancy at age 50 for men in various countries failed to find a significant relationship after controlling for one outlier. Furthermore, no statistically significant association was seen for women.
The bottom line is that at such a high level of aggregation and in the absence of suitable controls, it is not possible to demonstrate convincingly that international differences in levels of fitness or increased levels of physical activity are associated with international patterns of longevity. Given that the available data relate to levels of fitness and physical activity at only one point in time, it is impossible to assess the role played by fitness and physical activity in the divergent trends in life expectancy from 1980 to 2005. In contrast to the discussion of obesity in Chapter 3, the research base is not sufficient to identify a reasonable range of uncertainty in estimates of the contribution of physical activity to international differences in mortality. Physical activity may be an important determinant of mortality, significant in explaining cross-national differences and trends, but its role cannot be adequately evaluated with current data.