8-OHdG

8-hydroxy-2’-deoxyguanosine (8-OHdG) is the most studied biomarker of oxidative DNA damage, formed by hydroxyl radical attack on the C-8 position of guanine within DNA, and repaired and excreted as a urinary and salivary metabolite reflecting total body oxidative stress burden. In sport science, salivary 8-OHdG rises significantly after high-intensity exercise, particularly eccentric exercise and hypoxic training, providing direct evidence of exercise-induced reactive oxygen species attacking genomic integrity. Valavanidis et al. (2009) reviewed 8-OHdG as the gold-standard oxidative DNA damage biomarker with clinical and athletic applications.