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.