Strenuous Exercise Increases the Risk of Oxidative Stress in Ironman Triathlon Participants

Regular physical activity has been linked to greater overall health. Literature review and studies have also defined regular physical activity as a reducer of life-threatening illnesses such as cardiovascular disease, diabetes and obesity. However, long increments of strenuous exercise can produce oxidative stress and muscle fatigue in the human body. The increase in oxygen consumption during strenuous exercise leads to elevated reactive oxygen species (ROS). Cells continuously produce free radicals and reactive oxygen species as part of metabolic processes in the body. These free radicals are neutralized by an antioxidant defense system in the body consisting of enzymes, such as catalase, and non-enzymatic antioxidants. An Ironman Triathlon consists of a 2.4-mile (3.86 km) swim, a 112-mile (180.25 km) bicycle ride and a marathon 26.2mile (42.2 km) run, raced in that order and without a break. It is widely considered by athletes to be one of the most demanding sporting events in the world. It is hypothesized that a physically challenging event such as the Ironman Triathlon can be linked to elevated cortisol levels, increased occurrence of DNA damage, elevated concentrations of ROS, and consequently increased oxidative stress in humans. In order to derive conclusive results regarding the hypothesis, groups containing athletes who completed the full Ironman race, the half Ironman race, and a control group of moderately active individuals were established and individuals were required to report Garmin Smartwatch health and wellness data. The half Ironman consists of a 1.2-mile (1.93 km) swim, a 56-mile (90.12 km) bicycle ride and a marathon 13.1-mile (21.1 km) run, raced in that order and without a break. Several protocols were then applied to derive data necessary to complete the research. After the participants were selected, their saliva was collected in a non-invasive fashion and was used in the Elisa Saliva Kit to determine cortisol concentration. The saliva samples were also utilized to perform DNA and RNA extraction; and the resulting products were analyzed for quantity and quality of the DNA and RNA. Real time PCR allows scientists to monitor PCR while it is occurring. In this technique, luminescence is produced by reporter molecules as the PCR products increase with every cycle. To determine ROS concentration, the ROS-Glo assay, which provides a light signal that is proportional to the ROS in a given sample, was utilized. An additional marker of oxidative stress is 8-oxo-2-deoxyguanosine(8-oxo-dG). The OxiSelectTM Oxidative DNA Damage ELISA uses antibody and antigen interactions to report the concentration of 8-oxodG in a sample. Furthermore, the results indicate an increase in enzymatic indicators of elevated ROS, elevated cortisol levels, and disruption of sleep in the participating athletes after the race. In conclusion, the athletes who completed the full Ironman triathlon experienced increased amounts of oxidative stress than their less active counterparts in the control group, as was denoted by the elevated cortisol levels, increased 8-oxo-dG concentrations, and increased ROS concentrations. 1 Cutter et al.: Oxidative Stress in Endurance Athletes DOI: 10.7710/2168-0620.1144 Such a rigorous event negatively impacted participants and caused oxidative stress (Meeusen 2005).