Dr Kurl and colleagues1 found a strong inverse relation between cardiorespiratory fitness and risk of stroke in middle-aged men. However, among the plausible explanations of this beneficial effect, they did not mention the anti-inflammatory effect of physical activity.
There is mounting evidence that increasing fitness levels are associated with reduced levels of C-reactive protein, a sensitive marker of systemic inflammation.2,3 Since elevated levels of this marker seem to be related to an increased risk of stroke,4,5 the association between cardiorespiratory fitness and a reduced risk of stroke might also be mediated by the anti-inflammatory effects of physical activity.
Mascitelli L, Pezzetta F. Anti-inflammatory Effect of Physical Activity. Arch Intern Med. 2004;164(4):460. doi:10.1001/archinte.164.4.460-a