EFFECT OF EXERCISE ON BURST FREQUENCY A MARKER OF SYMPATHETIC ACTIVITY IN HYPERTENSIVE INDIVIDUALS: A SYSTEMATIC REVIEW.

Background: Burst frequency is a factor that is used to know the relationship between sympathetic activity and blood pressure in individuals with hypertension. Various forms of exercise reduce the burst frequency among individuals with hypertension. This systematic review provides suggestion of exercise prescription for reducing blood pressure. Objective: To determine the effects of exercise training and its regulatory mechanisms on burst frequency (BF) a marker of muscle sympathetic nerve activity (MSNA) in hypertensive individuals. Methods: A systematic literature search of electronic databases such as PubMed, Web of Science and Scopus was conducted from inception to July 2024 included randomized controlled trials (RCTs), non-randomized experimental studies (non-RCTs) or pre-post experimental trials on hypertensive patients without associated metabolic disorders, with or without pharmacological treatment, aged between 18 and 70 years, both genders. Patients underwent at least 4 weeks of aerobic, resistance, or breathing exercises with BF as an outcome measure were included. The Revised Cochrane Risk of Bias tool (RoB 2) and Risk of Bias in Non-randomized Studies of Interventions tool (ROBINS-I) was used to evaluate the risk of bias. Results: Five trials were included. Four studies demonstrated a significant reduction in BF among exercise-trained hypertensive individuals, while one study reported no change in BF. Overall, two studies had "some concerns" about performance and attrition bias, one had "high RoB" for selection bias, one had “moderate RoB” due to expected confounding, and one had “serious RoB” due to uncontrolled confounding factors. Conclusion: These findings suggests that HIIT significantly reduces BF, while aerobic and breathing exercises offers lesser benefits, further research should focus on training dosages. Implications: It provides evidence to utilize tailored exercise programme that may reduce sympathetic overactivity in hypertensive patients for better blood pressure control and reduce cardiovascular risk.