FMD , serum levels of isoprostanes , nitrite/nitrate ( NOx ) and sNOX@-dp , a marker of blood NOX@ activity , maximal walking distance ( MWD ) and maximal walking time ( MWT ) were studied in @ PAD patients ( @ males and @ females , mean age : @ years ) randomly allocated to @ g of dark chocolate ( > @ % cocoa ) or @ g of milk chocolate ( @ % cocoa ) in a single blind , cross-over design .