Perfectly correlation between economic health and physical health: the richer and more economically comfortable a country is, more time you have for your self.
In that same vein, I'd postulate that it's likely that more "modern" economies involve less physical labor, and there is thus a greater demand for after-hours exercise activities. In countries that are less "modern" and where agriculture and manufacturing might still be important, it is less likely that people would go out of their way to engage in physical activity. From a "values" perspective, one would probably point out that the economically healthier countries have more of their immediate, physical needs fulfilled (food, housing, income) and are now in the process of seeking personal fulfillment.
That said, such doesn't account for all of this; what I've read about the Baltics is that (at least in the 1990s) these service-heavy economies faced greater heart and health problems due to their diets and lack of preference for physical activity. Presumably, these are still remnants of the region's traditional past.
This also feeds into general assumptions about Protestant countries versus the rest of Europe, though we could go back and forth all day about the exact origins of this disparity.
