There are 2-3 known causes (don't remember them offhand, sorry), but they account for like 10% of all cases. Causes of the remaining 90% is unknown. 85 is not

There are 2-3 known causes (don't remember them offhand, sorry), but they account for like 10% of all cases. Causes of the remaining 90% is unknown. 85 is not high, but once it routinely crosses 90 they usually prescribe a low-dose medication to knock it down. This is to reduce the risk of excessive blood vessel wear.