'Sleep disorder suppresses sex drive'

Washington, Sep 13 : A diminished sex drive may be linked with chronic oxygen deprivation in patients of obstructive sleep apnea, especially during episodes of obstructed breathing.

University of Louisville (U-L) researchers found that after a week of being subjected to chronic oxygen deprivation (CIH), mice showed a 55 percent decline in their daily spontaneous erections. After five weeks of such exposure, average interval between mounting a mate increased 60-fold.

'Even relatively short periods of CIH are associated with significant effects on sexual activity and erectile function,' wrote David Gozal, professor of paediatrics at the U-L.

The study examined the behavioural and physiological effects in mice exposed to CIH for anywhere from five to 24 weeks. Control mice were kept under identical conditions, but were not subjected to nocturnal CIH.

The mice were evaluated on a series of complex sexual behaviours, including erection frequency and mating behaviour and biomarkers that may be affected by CIH, like testosterone and estradiol levels.

After just five weeks exposure to CIH, the gap between mounting times increased 60-fold. The potential to ejaculate was also severely affected.

In five out of seven mice tested, ejaculation did not occur at all, but in one mouse, gap between ejaculations was 11 hours whereas in control mice the median time was 'only a few minutes, said Gozal. Interestingly, one mouse appeared to be unaffected in this respect.

'The disparity in responses among mice is very similar to the heterogeneity of the magnitude of end-organ morbidity in sleep apnea among patients, and shows that not everyone will be affected to the same extent,' said Gozal.

Even after six weeks' recovery time with standard oxygen levels, mice exposed to CIH for as little as one week only recovered 74 percent of their original erectile function, wrote Gozal. The results appeared in the September edition of the American Journal of Respiratory and Critical Care Medicine.

Despite the lingering negative effects of CIH on sexual behaviour in mice, the researchers did find that it was largely reversible. In the second phase of the experiment, Gozal administered tadalafil, which improved erectile and sexual functioning in CIH-exposed mice to near-normal levels in almost all cases.