[SOAPBOX]
I am not a doctor, but I am very interested in health policy, and really concerned with the crazy numbers of people who are diagnosed with "high blood pressure" these days.

Over the past 20 years, the threshold for "high" in blood pressure measurement has gone down every time they revised the guidelines. There is very strong pressure on the part of the pharmaceutical industry to keep on lowering the numbers (and increasing the number of people on meds, hence the shareholder benefits). A lot of people are getting medication instead of a prescription for lifestyle change (diet, exercise, stress reduction...). Of course, it's easier to be compliant with taking pills than changing your lifestyle... Many of my doctor-friends are really concerned with the epidemics - of prescription, not of HBP. There is at least as much politics and economics behind those guidelines than actual medical knowledge...

So bottom line, for me, is: ride, make sure you eat well and probably loose some weight, reduce your stress (which will also help you eat, sleep better) and do that for a few months to see if it positively affect your blood pressure before going on medication.

And if you do go on medication, I'd suggest you make sure you ask your doctor about the REAL reduction in risk of heart problems. It's probably much less than some people would like us to think. You need this information to make an informed decision. And ask many questions about the specific med prescribed. Some cost nearly nothing, some (newer ones) are really really expensive, and not necessarily much more efficient.
[/SOAPBOX]

And, by the way, last time I got my blood pressure measured, I had had a fast ride just 2 hours before. 150/110 was the reading. Nobody panicked, doctor just told me to check it again sometime when I walk in a pharmacy...