THE EFFECT OF COFFEE ON HEART RATE VARIABILITY

Background: Although the effects of coffee on the autonomic nervous system have been well documented, there exists as yet no conclusive data on the effects of the consumption of coffee on heart rate variability (HRV). The objective of this study was to determine the effects of coffee on these parameters among south Indian subjects. Methods: This interventional study involved a single group of fifty male subjects aged between 18 and 25. The subjects underwent a set of baseline tests that included recording of the heart rate (HR), blood pressure (BP) and HRV indices. They were then given coffee and fifteen minutes later the same set of tests were performed. Results: We observed that coffee significantly increased the HR and systolic BP and reduced the diastolic BP. We noticed an increase in HF power, a reflection of parasympathetic activity, but the increase was not statistically significant .Coffee did not have a significant effect on any of the other HRV parameters. Conclusions: We concluded that coffee stimulates the sympathetic nervous system.