There is substantial evidence in the literature that the adoption of a sedentary lifestyle, obesity, ageing and chronic diseases lead to an attenuation of endothelial NO production by reductions in eNOS expression and protein content (McAllister & Laughlin, 2006) and increases in NAD(P)Hox expression and protein content (Brandes & Kreuzer 2005, Silver et al. 2007) in the macrovasculature.