During exercise stress test , systolic pressures should raise at least by 20-40mmhg.(Max 60 mm from baseline ) Diastolic BP will remain at baseline or show a marginal elevation or even a miniscule fall.This is primarily due to increased cardiac out-put , mediated by demand and dilatation of musculature in exercising muscle.
If the systolic BP falls or does not raise during exercise , it implies either poor LV function , vascular insufficiency or autonomic dysfunction.
If there is a fall of > 20mm , even in the first stage, accompanied by chest discomfort or giddiness with ECG changes ,it could be an ominous sign of serious left main or a tight proximal LAD disease and test should be terminated immediately.
Paradoxically , If BP raises more then 200 at any time we call it hypertensive response and may be a risk factor for future onset systemic HT or even a stroke. ( Stress test not only help us detect ischemia of heart ,it also can reveal how the vascular system would handle and adopt to increased cardiac output at time of hemodynamic demands)
Physical de-conditioning is an important cause for hypertensive response , as the entire vascular system lacks dynamism (Vascular tone ) , a precursor for hypertension, endothelial dysfunction and cardio vascular events..