Endocrine Abstracts

Introduction: In order to study the effect of age and testosterone on sleep related erections, we enrolled 209 men (122: age 30–49 years; 87: age over 50 years), including mild and severe hypogonadal subjects (129) and eugonadal subjects (80).

Subjects and methods: The subjects were assigned to four groups, according to their testosterone serum levels. All the subjects underwent nocturnal penile tumescence and rigidity monitoring (NPTRM). The following sleep-related erection parameters were analyzed: total number of valid erections, total duration of rigidity >60%, total duration of increase in penile tumescence >30 mm, maximum rigidity and maximum increase in penile tumescence.

Results: Total number of valid erections, total duration of rigidity >60% and total duration of increase in penile tumescence >30 mm showed constant lower values in the 4 groups of men over 50 years, when compared with the 4 groups of men with age range 30–49 years and with the same testosterone level. Moreover, when comparing groups of men with same age but different testosterone levels, a threshold was identified still for the previous 3 parameters: the more the T is lower than 8 nmol/L, the more sleep-related erections are impaired, but this pattern is lost when T is higher than 8 nmol/L. On the other hand, maximum rigidity and maximum increase in penile tumescence showed the same trend of the other parameters when groups with different age range are compared, but these 2 parameters were uninfluenced by testosterone levels.

Conclusions: Aging has an impairing role on sleep-related erections both in hypogonadal and eugonadal men, while testosterone has an higher effect only on some of the parameters we investigated.