Sounds to me like a form of the dreaded "white coat syndrome". One of our doctors told me of one of his patients whose blood pressure shot up so drastically that they nearly called an ambulance. In his case it was a conditioned reaction inflicted on him by parents who would scare him with what doctors etc would do to him if he was naughty. But variations on the theme are common.

The fact that you obviously have no blanket reaction to doctors at work makes it seem less easy to explain, but the reactions are hard to pin down (if you excuse the expression) In some people the effect takes the form of fainting at the smell of ether or meths.

One time when I was having an assessment, my blood pressure was so high the nurse rang someone up to see if it was safe for me to drive home. The next day my GP checked it and it was low-to-normal. I think they need their machines calibrating!

OK. So my BP drops through the floor when they stick me, and shoots through the roof when they measure it. That's crazy - maybe I have quantum blood?

But what's the reason ? How can BP fluctuate so much in such short periods? I'm not fazed by needles, but once the blood goes into that little tube I'm woozing.

And as one of the vital signs that medics always measure, how useful is measuring BP when readings can be so variable.