Effects of Long-term Strenuous Exercise on Oxidative DNA Damage and Proteinuria in Humans
The purpose of this study consisting of three projects was to determine the effects of long-term strenuous exercise on oxidative DNA damage and proteinuria in trained individuals. In the first project, four successive triathlons accompanied by long-term training in a triathlete was chosen as the experimental design and procedure. In the second project, repeated 5-h bouts of cycling exercise at 52 %VO2peak and a 40 km time trial with carbohydrate and potential antioxidant supplementation (fenugreek seed extract) were carried out with trained individuals. In the third project, a wildland firefighting three-day work shift was conducted with active duty military personnel. Assessment of oxidative DNA damage was based on urinary and muscle 8-hydroxy-2'-deoxyguanosine. Post-exercise proteinuria was determined with several biomarkers including urinary total protein, albumin, beta2-microglobulin, N-acetyl-beta-D-glucosaminidase, and creatinine. The overall results showed that there were significant whole-body DNA oxidation and post-exercise proteinuria after the half- and full-Ironman triathlon races, but these levels gradually returned to baseline. In contrast, no significant alterations were observed in either oxidative DNA damage at the muscle and tissue level or proteinuria after the 5 h of cycling exercise at 52 %VO2peak and the 40 km time trial. Arduous work during wildland fire suppression induced proteinuria, which tended to be accumulated as the work shift progressed. These findings indicate that moderate exercise may not reach the threshold to cause oxidative DNA damage and proteinuria, whereas long-lasting strenuous exercise appears to induce oxidative DNA modification and exceed normal range of urinary protein excretion.
Advisor:Dr. Brent Ruby; Dr. Blakely Brown; Dr. Elizabeth Putnam; Dr. Fernando Cardozo-Pelaez; Dr. Kent Sugden
School:The University of Montana
School Location:USA - Montana
Source Type:Master's Thesis
Date of Publication:12/28/2007