Relationship between Autonomic Nervous System Activity and Lower Urinary Tract Symptoms: An Analysis of Heart Rate Variability in Men with Lower Urinary Tract Symptoms

Objectives: Lower urinary tract symptoms (LUTS) are common, but their etiology and mechanism remain unclear. We believe that changes in autonomic nervous system (ANS) activity may be contributory because the lower urinary tract is regulated through the sympathetic and parasympathetic nervous systems. Heart rate variability (HRV) is a tool by which autonomic nervous function can be measured; therefore, we measured and compared parameters of heart rate variability between men with LUTS and asymptomatic subjects. Methods: We studied 35 men with LUTS (mean age 50.5 +/- 14.9 years) and 110 asymptomatic male volunteers who had requested a health check up (mean age 49.5 +/- 5.19 years) from July 2006 to June 2008. HRV is known to be a useful tool for evaluating ANS activity, and we measured and compared HRV in the resting state. Results: The standard deviation of the N-N interval (SDNN) and total power (TP) for patients with LUTS revealed no significant differences from those in the control group. On frequency domain analysis, there was evidence of decreased high frequency (HF) in patients with LUTS (P < 0.05), but there were no significant differences in other parameters, such as heart rate, square root of the mean squared differences of successive N-N intervals (RMSSD), very low frequency (VLF), low frequency (LF), or LF/HF ratio. Conclusion: Patients with LUTS exhibited different HRV parameters compared with asymptomatic controls. Their decreased HF indicated that they may have had an imbalance in the autonomic nervous system.