A. From H. Ballentine Carter, M.D., professor in the department of urology and oncology and director of adult urology, Johns Hopkins University School of Medicine, Baltimore:
The PSA, or prostate-specific antigen, is a protein secreted by the prostate gland that’s often elevated if a man has a prostatic disease, including prostate cancer. For this reason, some medical groups and doctors recommend that middle-aged and older men (usually up to age 75) have a regular PSA screening. But can a cycling excursion skew the results of this blood test? Some researchers have speculated that sitting on a bicycle seat puts direct pressure on the prostate and perineum (the area between the scrotum and the anus), resulting in an elevated PSA.
Related Video: Bike Safety Tips
The landmark paper on the topic was published in 1996. In the study, researchers measured the PSA levels of 260 volunteers before and after a four-day, 250-mile bicycle ride in the Colorado Rocky Mountains. The participants had no significant increase in PSA after their ride, with the exception of four men who had an already elevated PSA before they started.
Even in those four men, the difference was modest and would not influence decision making. If cycling caused prostate trauma that made a significant difference in PSA, this study would have found it.
I would suggest that for most men, bicycling—outdoors, indoors on an exercise bike or in a cycling class—would make no difference whatsoever in PSA levels.