title: Effects of repeated bouts of long-duration endurance exercise on muscle and urinary levels of 8-hydroxy-2'-deoxyguanosine in moderately trained cyclists.
abstract: The purpose of this study was to determine the effects of repeated bouts of long-duration endurance exercise on both muscle and urinary levels of oxidative DNA damage in moderately trained individuals. Seven moderately trained male cyclists participated in this study. All participants repeated two sessions consisting of a 5-h cycling period (equivalent to approximately 52%[Formula: see text]O2peak) followed by a 15-h rest, then a 40-km time trial. During the sessions, participants were instructed to take water ad libitum and to consume a standard sports drink consisting of 0.12 g·kg(-1) body weight·hr(-1) of carbohydrates. For each session, 24 h urine output was collected on the day before the 5-h exercise, and also between the 5-h exercise and 40-km time trial, in addition to between days 1-5 post-exercise. Subsequently, muscle and urinary levels of 8-hydroxy-2'- deoxyguanosine (8-OHdG) were determined using high performance liquid chromatography with electrochemical detection. No significant alterations were observed between two sessions at the muscle or urinary levels of 8-OHdG. These results suggest that repeated bouts of exercise with a 7-day washout period may not lead to an accumulation of DNA damage products after a second 5-h stationary cycling bout.
authors.affiliation: a Departments of Health and Human Performance , The University of Montana , Missoula , MT , USA.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Yasuda
authors.forename: Celeste
authors.initials: C
authors.lastname: Bolin
authors.forename: Fernando
authors.initials: F
authors.lastname: Cardozo-Pelaez
authors.forename: Brent C
authors.initials: BC
authors.lastname: Ruby
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D017209:Apoptosis; D001642:Bicycling / Q000502:physiology; D004249:DNA Damage; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000652:urine; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D055815:Young Adult
chemical_list: D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine
keywords: DNA oxidation; apoptosis; exercise intensity; oxidative stress; ultra-endurance exercise