A little known fact is that Erectile Dysfunction is linked to Sleep Apnea. The incidence of ED in men with sleep apnea is in excess of 50% in most studies. The reasons for this problem appear to be two fold. In some men, Sleep Apnea can cause low testosterone levels. In others, repetitive drops in oxygen cause a problem with the ability of small blood vessels to supply adequate blood flow to the penis. This is called endothelial dysfunction and is very common in Sleep Apnea. The good news is that the majority of persons afflicted with Sleep Apnea will show significant improvement in sexual function when their Sleep Apnea is treated. This has been clearly demonstrated in several studies.