OP, just curious, how are you measuring your heartrate?
I think the cheapest HRM enabled watch is around $30. But the OP's method works OK enough to set off alarm bells. 160 ought to be a race-pace heartrate or damn near for a guy his age.
so for the past year your HR has been skyrocketing when you walk slightly faster than normal and you never thought this is something you should go see a doctor about? where you also dropped on your head multiple times as a child? the **** is wrong with some people?