Objective: 1) To assess hemodynamic responses and baroreflex sensitivity (BRS) indices during Valsalva maneuver (VM) and head-up tilt (HUT) testing in orthostatic intolerance (OI). Methods: Patients with neurogenic orthostatic hypotension (NOH, n=26), postural tachycardia syndrome (POTS, n=26) and symptomatic orthostatic intolerance (SOI, n=14) were compared to healthy population (Control, n=107) and inappropriate sinus tachycardia (IST, n=7). Hemodynamic assessment included patterning and quantification with vagal and adrenergic BRS (BRSv and BRSa/BRSa₁). Results: In NOH, cardiovagal SBP decrements in VM and HUT were correlated (r=0.660, p<0.001); a "V" pattern of VM indicated alpha BRSa failure. Yet, BRSa₁ did not reveal changes vs. Control (p>0.05) or was not applicable in 60% of NOH. In SOI, compared to Control cardiovagal SBP decrements were larger (p<0.05); higher BRSa₁ contradicted higher adrenergic index (CASS). Overshoot in phase IV dipped below baseline or dropped ≥ 10 mmHg over 8 s in POTS ("N" pattern), but by 3 s in IST ("M" pattern"). Conclusions: Visualization of distinct VM patterns allows primary evaluation of autonomic dysfunction and differentiation of the various forms of OI. BRSa₁ evaluation is compromised by pathological SBP patterns. Significance: VM patterning is a valuable non-postural supplement to HUT capable of detecting and differentiating OI.