Normal Variations in Episodes and Duration of Nocturnal Penile Tumescence Among Iranian Men: A Descriptive Analytical Study

Background: Erectile dysfunction (ED) in men is a significant issue that can profoundly impact personal relationships, mood, and overall quality of life. The nocturnal penile tumescence (NPT) test is a valuable tool for distinguishing between psychological and physiological causes of ED. The normal values of the NPT test are a subject of debate across various racial groups. Therefore, there is a need to conduct a study in the Middle East region to establish standard norms for NPT. Objectives: The aim of this study is to investigate the results of the NPT test in sexually healthy Iranian men. Methods: This descriptive study involved the examination of 30 sexually healthy Iranian volunteers using the iranian erection analyzer over a period of two nights. In this study, a NPT episode was defined as radial rigidity exceeding 70%. The frequency and duration of these episodes were documented and subjected to analysis. Results: The average number of tumescence episodes per participant on the first and second nights was observed to be 1.73 ± 0.82 and 1.9 ± 0.66 episodes, respectively. The average duration of each tumescence episode on the first and second nights was found to be 16.04 ± 7.7 and 22.08 ± 6.85 minutes, respectively. A statistically significant difference in tumescence duration was noted between the two nights (P < 0.001), with the second night showing higher values. Furthermore, it was determined that 83.4% of sexually healthy men experienced 1 to 2 episodes of tumescence during the night. Conclusions: The findings of this study indicate that the majority of sexually healthy Iranian men experience 1 to 2 episodes of NPT with rigidity surpassing 70% overnight, with an average duration of 16 to 22 minutes per episode. Additionally, the study suggests that relying on a single-night NPT test may be inadequate for an accurate assessment.