The time in which a man is able to remain in the vagina during intercourse with movement of the penis is scientifically called the Intravaginal Ejaculatory Latency Time (IELT).
So far a mathematical formula of human ejaculation time did not exist. Janssen and Waldinger compared the IELT distribution of men in the general adult population with the IELT distribution of Dutch men with lifelong Premature Ejaculation (PE). IELT was measured with a stopwatch by their female partners in both group (Investig Clin Urol. 2016 Mar;57(2):119-128).
According to Waldinger and colleagues, the IELT distribution of men in the general population is most accurately fitted by the lognormal distribution, whereas the IELT distribution of men with lifelong PE is most accurately fitted by the Gumbel Max distribution. According to the formula, it is calculated that in the general male population, only 1.08% of men ejaculate between 0 and 60 seconds. In contrast, in men with lifelong PE, 85.4% of men ejaculate within 1 minute, indicating that lifelong PE has a distinct IELT distribution.
Lifelong PE has been shown to be a very stable putative endophenotype within the range of all IELT’s measured across the world in different populations and cultures. The newly calculated mathematical different distribution model of the IELT in the general population and lifelong PE males strongly support biological differences underlying these IELT distributions and argue against psychological or behavioral interventions aimed to lengthen the IELTs in PE males.
Investigative and Clinical Urology is the official journal of the Korean Urological Association. For more information, please visit http://www.icurology.org, or contact Prof. Dr. Marcel D. Waldinger at firstname.lastname@example.org.