Introduction Why some individuals with similar demographic characteristics develop syncope during tilt testing (TT) and others do not is unknown and low test sensitivity is claimed. We sought an alternative explanation; resting cardiovascular physiology differs in patients with positive and negative TT. Methods We analyzed age, gender, systolic (SBP), diastolic blood pressure (DBP), and heart rate (HR) using three large syncope patient databases comparing tilt-positive with tilt-negative results after excluding orthostatic hypotension. Positive tilt-response, confirming reflex syncope, was defined as reproduction of spontaneous symptoms with characteristic bradycardia and/or hypotension. Impact of demographic, hemodynamic parameters and prevalent hypertension on TT positivity were assessed using logistic regression models. Results Records of 5236 patients (45% males; mean age, 60±22 years; 32% on antihypertensive therapy) were analyzed. TT was positive in 3129 (60%) and tilt-positive patients had lower SBP (127.2±17.9 vs 129.7±18.0 mmHg, p<0.001), DBP (76.2±11.5 vs 77.7±11.7 mmHg, p<0.001) and HR (68.0±11.5 vs 70.5±12.5 bpm, p<0.001) compared with tilt-negative patients. SBP was similar in males and females but males had higher DBP and lower HR than females (p<0.001). In multivariable analysis, tilt-test positivity was independently associated with younger age (p=0.016), SBP≤128 mmHg (p<0.001), HR≤69 bpm (p<0.001), and absence of hypertension (p<0.001). Conclusions Patients developing reflex syncope during tilt-testing have lower systolic and diastolic blood pressure and heart rate compared with tilt-negative patients. Tilt-test positivity is independently associated with younger age, lower blood pressure, lower heart rate and absence of hypertension but not with gender. These hemodynamic differences imply hypotensive susceptibility.