@article{ref1,
title="Long distance bicycle riding causes prostate-specific antigen to increase in men aged 50 years and over",
journal="PLoS one",
year="2013",
author="Mejak, Sandra L. and Bayliss, Julianne and Hanks, Shayne D.",
volume="8",
number="2",
pages="e56030-e56030",
abstract="OBJECTIVES: To investigate whether bicycle riding alters total prostate-specific antigen (tPSA) serum concentrations in healthy older men. <br><br>METHODS: 129 male participants, ranging in age from 50 to 71 years (mean 55 years), rode in a recreational group bicycle ride of between 55 and 160 kilometers. Blood samples for tPSA analysis were drawn within 60 minutes before starting, and within 5 minutes after completing the ride. The pre-cycling and post-cycling tPSA values were log transformed for normality and compared using paired t-tests. Linear regression was used to assess the relationship between changes in tPSA with age and distance cycled. <br><br>RESULTS: Bicycle riding caused tPSA to increase by an average of 9.5% (95% CI = 6.1-12.9; p<0.001) or 0.23 ng/ml. The number of participants with an elevated tPSA (using the standard PSA normal range cut-off of 4.0 ng/ml) increased from two pre-cycle to six post-cycle (or from five to eight when using age-based normal ranges). Univariate linear regression analysis revealed that the change in tPSA was positively correlated with age and the distance cycled. <br><br>CONCLUSIONS: Cycling causes an average 9.5% increase in tPSA, in healthy male cyclists >= 50 years old, when measured within 5 minutes post cycling. We considered the increase clinically significant as the number of participants with an elevated PSA, according to established cut-offs, increased post-ride. Based on the research published to date, the authors suggest a 24-48 hour period of abstinence from cycling and ejaculation before a PSA test, to avoid spurious results.<p /> <p>Language: en</p>",
language="en",
issn="1932-6203",
doi="10.1371/journal.pone.0056030",
url="http://dx.doi.org/10.1371/journal.pone.0056030"
}