Transcutaneous penile oxygen pressure during bicycling

Objective To evaluate the blood supply to the penis during bicycling and th us determine whether the associated perineal compression might be responsib le for some cases of impotence. Subjects and methods The transcutaneous penile oxygen partial pressure (pO( 2)) at the glans of the penis was measured in 25 healthy athletic men; pO(2 ) is readily measured by noninvasive techniques currently widely used in th e management of premature infants, and which have been shown to give pO(2) levels that correlate with arterial pO(2) levels. The measurements in the h ealthy subjects were taken in various positions, before, during and after b icycling. Results The mean (SD) pO(2) of the glans when standing before cycling was 6 1.4 (7.2) mmHg; it decreased after 3 min of cycling to 19.4 (4.7) mmHg. Aft er 1 min of cycling in a standing position it increased significantly to 68 (7.6) mmHg; when cycling was continued in a seated position, after 3 min t he pO(2) fell to 18.4 (4.2) mmHg and there was a full return to normal pO(2 ) values after a 10-min recovery period. Conclusion The pO(2) seems to correlate with the blood supply to the penis. The present results support the hypothesis that as the penile arteries are compressed against the pubic bone by the saddle during bicycling, the pO(2 ) values decrease. Additionally, shifting from a seated to a standing posit ion while cycling significantly improved the pO(2) value of the penis and p enile blood oxygenation was then even greater. Therefore, we suggest that c yclists change their body position frequently during cycling. Correcting th e handlebars or the height of the saddle, tipping the nose of the saddle to produce a more horizontal, or even downward pointing position, and attenti on to the design of the saddle may be the only required precautions.