I have never had prostatitis but I am a prostate cancer survivor and my oncologist is just thrilled to death that I am doing all this riding. He is an avid cyclist himself. Since my cancer treatments, my PSA is extremely good and my oncologist is encouraging my riding. I couldn't have surgery to remove the prostate because of another illness, but normally the prostate (if not removed) will remain large after cancer. Mine has actually shrunk. I can't say that it is because of the riding, but the riding certainly is helping. I know that everyone is different, but in any case, you should consult with your doctor if you want a definitive answer.