title: The effect of bicycle riding on serum prostate specific antigen levels.
abstract: OBJECTIVE
  We determined if bicycle riding causes an increase in prostate specific antigen (PSA) levels.
  
  
  METHODS
  Baseline PSA levels were measured from all 260 volunteers before a 250-mile bicycle ride. After this 4-day race PSA was again measured and this level was compared to the pre-race levels.
  
  
  RESULTS
  The overall change from baseline to post-race PSA in all 260 men was 0.069 ng./ml. The change for the 256 men with normal baseline PSA (0.0 to 4.0 ng./ml.) was 0.044 ng./ml. The 4 men with an already elevated PSA (more than 4.0 ng./ml.) showed a large change of 1.65 ng./ml.
  
  
  CONCLUSIONS
  There is no statistically or clinically significant increase in PSA after bicycle riding. However, the few participants with an initially elevated PSA had an increase after bicycle riding, although this change does not represent the population and more research is warranted to define further its clinical implications.
authors.affiliation: Department of Urology, Presbyterian St. Luke's Hospital, Denver, Colorado, USA.
authors.forename: E D
authors.initials: ED
authors.lastname: Crawford
authors.forename: S H
authors.initials: SH
authors.lastname: Mackenzie
authors.forename: H R
authors.initials: HR
authors.lastname: Safford
authors.forename: M
authors.initials: M
authors.lastname: Capriola
mesh_terms: D000328:Adult; D000368:Aged; D001642:Bicycling / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood*
chemical_list: D017430:Prostate-Specific Antigen