He stated that my tunnel vision etc, could have been caused by a drop in BP due to exertion of exercise and decreased salt, or increased water (which flushes what salt you have out).
Like I said, your BP isn't supposed to drop during exercise. It isn't unreasonable to see if staying hydrated helps.
Tadawdy according the American Heart Association low blood pressure is not a "condition" as high blood pressure is.
Right. It's not a problem unless it's a problem.
Resting EKG is of limited value. Resting blood pressure is not a way of evaluating cardiac response to exercise. Problems at rest could be contraindications to exercise, but the absence of problems at rest doesn't mean a thing in regard to exercise.
I'm not saying you have some huge problem. I was just saying that if the doc actually thought someone had a drop in BP during exercise (abnormal), dismissing it based on resting measures is really just a way to placate someone. GP's do it all the time (especially in younger patients) and they are right the great majority of the time.
I can, however, imagine scenarios in which a bike commuter could have a sudden drop in BP. Combine high heat with poor hydration (common in the morning) and a sudden stop in effort (like at a light), and you could have blood pooling leading to syncope.