Comparison of cardiovascular autonomic activity (heart rate variability and baroreceptor sensitivity) in young healthy females during fasting and hyperglycaemia

Abstract Background and Aim The present study compared cardiovascular autonomic activity and reactivity during fasting (FS) and hyperglycemia (HS) states in young healthy females. Methods This case crossover study was conducted on 30 females recruited by convenient sampling. Blood glucose levels were measured in FS and after oral glucose load i.e., HS. Finger arterial blood pressure (BP) and ECG were recorded constantly to monitor baroreceptor sensitivity (BRS) and heart rate variability (HRV). Autonomic reactivity was tested with deep breathing (DB), Valsalva manoeuvre (VM), and head-up-tilt (HUT) test under FS and HS. HRV parameters not normally distributed were natural log (ln) transformed. Results Significantly reduced Valsalva ratio and higher heart rate and BP were observed in HS that continued during HUT (P  Conclusion Compared to FS, the HS exhibited heightened sympathetic activity with attenuation of parasympathetic activity and this phenomenon was further accentuated by HUT. BRS was more sensitive indicator of autonomic effects of hyperglycemia in resting state. In addition to standard tests, autonomic reactivity in vulnerable young subjects could be useful to detect autonomic imbalance at an early stage.