Predicting future heart attacks or strokes is very difficult and makes it difficult to study medications that could have a preconditioning effect. However, it has recently been recognized that we can mimic the preconditioning effect in the human arm, by blocking blood flow using a blood pressure cuff under pressure. Here, blowing up the cuff for 5 minutes and then letting the pressure out for 5 minutes and repeating this process twice more (a way to precondition the arm), has been shown to improve blood vessel function in response to a longer period of blood pressure cuff inflation (20 minutes).