Background: For a long time, researchers have employed head-up tilt to analyze how the heart and blood pressure react to different positions. The vasovagal reflex is responsible for the most prevalent type of reflex syncope, known as vasovagal syncope (VVS) or neurocardiogenic syncope. Objective: The goal of teaching patients to notice prodromal symptoms and doing suitable physical counter-maneuvers (PCMs) to increase blood pressure in order to prevent or postpone attacks is to reduce the likelihood of future attacks. Patients and methods: In a case-control study, fifty-seven subjects were enrolled in the study. Thirty-five patients were in 1st case group with recurrent history of presyncope or syncope and positive tilt test. Twenty-two age matched healthy subjects were in 2nd control group. All underwent head up tilt testing (HUTT). Results: there was a statistical significance increase in LF power during P2 in cases compared to controls and also significant increase in LF/HF ration in P1 and P2 reflecting the high sympathetic predominance just preceding the episode of syncope. The magnitude of effect of LFP2, LF/HF at rest and Δ LF between P2 and P1, Δ LF/HF between P1 and R was high denoting the rapid autonomic alteration resulting from postural and stressful conditions preceding the occurrence of syncope. Conclusion: Variability in heart rate provides information about the autonomic nervous system's health (ANS). How much the heart rate (HR) varies tells us about how well the nervous system regulates the heart rate and how quickly the heart can react to external stimuli.