Aim: 

Penile erections are physiological hemodynamic events due to penile arteries dilatation and smooth muscle fiber relaxation caused by neurological, neurochemical and endocrine mechanisms. Sleep-related erections (SREs) occur during REM phase and their measurement is commonly used to discriminate between psychogenic and organic erectile dysfunction. The aim of this study was to evaluate the altitude effects on SREs in order to estimate the role of hypoxia in erection physiology.

Methods: 

SREs were recorded by RigiScan on a mountain climber during 43 consecutive nights at different altitudes, from 0 to 5050m a.s.l. Erections number and duration, tumescence activated unit and rigidity activated unit, event duration (% of session), event rigidity %, time rigidity 60-100%, event tum %>bline (%) and average rigidity 0-59% were assessed. The subject was equipped with a BodyMedia's SenseWear™ armband in order to evaluate sleep quality.

Results: 

No significant differences were observed comparing total sleep times and rough sleep efficiencies approaching to base camp (5050m) to values detected during base camp sojourn. Our data do not support the hypothesis of altitude-induced modifications in total amount and quality of sleep. On the opposite, during base camp approach to and at base camp, the erectile parameters showed an altitude-correlated reduction. The return to sea level reverted these functional alterations.

Conclusion: 

Our results seem to suggest that oxygen availability and delivery could play an important role in the regulation of local penile erection-related mechanisms and that low oxygen levels may be considered an etiological factor in erectile dysfunction.