We aimed to assess whether cycling increased PSA in a large sample of men (n = 129) at an age where prostate screening is commonly conducted (≥50 years), while being representative of typical distances cycled for recreation and fitness (≥55 km), and ensuring that the time elapsed before post-cycling PSA testing was minimized, to eliminate the chance of serum clearance. The gene discussed is KLK3; the disease is male reproductive organ cancer.