Sleep Apnea and Erectile Dysfunction
ED or erectile dysfunction is often associated with
sleep apnea. Some new research indicates that erectile dysfunction associated
with obstructive sleep apnea syndrome (OSAS) may be caused by chronic
intermittent hypoxia-oxygen deprivation (CIH), an effect of sleep apnea that
plagues men who have obstructive sleep apnea.
In an experiment designed to test this hypothesis, University of Louisville researchers discovered that after seven days of exposure to CIH which resembled that in a man with obstructive sleep apnea, male mice had a fifty per cent reduction in the number of spontaneous daily erections. And after thirty five days of exposure, the time it took male mice to mount a mate had increased by a factor of sixty times.
David Gozal, MD, professor at the University of
Louisville, commented that it appeared even relatively short periods of CIH
could have a major impact on sexual activity and the male's ability to become
erect. The research work looked at the effects on behavior and physiology of
mice exposed to CIH for periods ranging from thirty five days to more than
twenty weeks. A group of control mice were not exposed to the same stimulation
and did not experience CIH. The mice were all examined for changes in sexual
behavior, as well as the number of erections they developed and how their mating
behavior was affected. A number of physiological parameters such as testosterone
and estradiol levels were examined, together with endothelial and neuronal
nitric oxide synthase activity. These compounds play an essential role in the
mechanism of erection. These compounds are abbreviated to eNOS and nNOS; eNOS is
a molecule whose levels are raised by Viagra, and it plays a major part of the
male sexual physiology.
Dr Gozal added that the variation in responses between mice mirrors the variation between men, who show very different responses to sleep apnea, and who clearly do not all experience the impact on erectile function to the same degree. There were no significant changes in testosterone and estradiol levels in the experimental mice, although there was a decrease in eNOS expression in the mice which were subjected to CIH for fifty six days.
Even more interesting, after as little as one week's exposure to sleep apnea, and a recovery period of forty two, the mice had only regained about three quarters of their original capacity for erections. This implies there is some permanent effect or that longer recovery time is required. In any even, the impact f sleep apnea on erectile function is severe, and it looks like a major cause of erectile dysfunction in men.
Given enough time, the effects of sleep apnea were reversible. Using a drug commonly prescribed for erectile dysfunction, tadalafil, which works by increasing the availability of nitric oxide through PDE5, the mice were restored to normal sexual and erectile functioning, so that the impact of CIH was almost completely reversed. This applied to all aspects of sexual behavior, including time to mount, penetration and time to ejaculation as well as number of erections and spontaneous erections. The point here being that tadalafil affected both erectile physiology and mating behavior. This could indicate that PDE5 has a role in the central nervous system control of sexual behavior.
Dr Gozal indicates that more research is needed
to elucidate the relationship between sexual behavior, sexual physiology and
sleep disruption and episodes of hypoxia during sleep. This is incredibly
important for men with erectile dysfunction, because CIH is a very common
occurrence in OSA. In summary, though, erectile dysfunction appears to be yet
another dysfunction associated with - and most likely caused by - obstructive
sleep apnea. And even though this work was done on mice, chronic intermittent
hypoxia has some very profound impacts on multiple organ systems, which make it
extremely likely that the same effects apply to humans. This means that early
identification of the condition and application of some effective therapy for
OSA is extremely important for regulating erectile dysfunction in men who suffer
form both conditions.
Other sections on the website about erectile dysfunction