You may want to print this chart out.

Take your blood pressure and subtract the lower number (diastolic) for the higher number (systolic) .   Take that number, and locate on the left (vertical) part of the chart.  Go across from that line, and make a mark where it intersects the curve on the graph.  Now draw a straight line down from that point to find your heart's biological age.  This may be years younger or older than your actual age.

Example:  Let's say that your blood pressure is 140 over 80.  140-80 = 60. 

Find 60 0n the left part of the graph, then go across to the curve, then down to find your heart's biological age of 62.