Background: Postural Orthostatic Tachycardia Syndrome (POTS) is the increase in heart rate (HR) by ≥30 bpm within 10 minutes of upright posture without orthostatic hypotension (OH). This study specifcally investigated patients who develop delayed symptomatic orthostatic tachycardia (i.e. after >10 minutes) without OH. Methods: Clinical histories and laboratory tests of patients assessed for orthostatic intolerance (OI) during last 10 years were reviewed. All patients underwent autonomic tests (sweat test, heart rate variability to deep breathing/Valsalva, 45-minute head up tilt table test (TTT) and quantitative sensory testing. Results: Among 974 patients with OI, 43% (419/974) were diagnosed with POTS whereas 12.4% (121/974) had delayed orthostatic symptoms on TTT alongwith delayed orthostatic tachycardia (DOT; x¯ = 30.3 minutes) without OH. In this cohort, mean HR increase was 51.7 bpm (range: 40-104 bpm). Other findings were significant narrowing of pulse pressure (PP) i.e. ≤25% of systolic pressure (x¯ = 16.2%, range: 6.4% -24.3%), excessive BP oscillations and syncope (9.9%). About 1/3 (37.2%) with DOT had definite small fiber/autonomic neuropathy. Conclusions: Patients with OI may manifest delayed symptoms/DOT and maybe missed on a 10-minute TTT. The marked reduction in PP observed in these pateints signifies reduced cardiac output, possibly from peripheral blood pooling due to small fiber/autonomic neuropathy.