Search

The increase in oxygen uptake during aerobic exercise is accompanied by an elevation in free radical oxygen. However, long-term endurance training reduces the damage associated with oxidative stress by enhancing the body's antioxidant defenses, including levels of reduced glutathione (GSH). Sleep deprivation can also induce oxidative stress, leading to increased oxidation of GSH. A seasoned athlete competed in ultra-endurance events in consecutive years (2013 and 2014). During the first event, the subject performed well but slept an average of only 1.6 hrs ⋅ d-1. Following the event, he experienced significant fatigue. During the second event, the subject slept 4.9 hrs ⋅ d-1 and performed even better. Furthermore, he reported no significant post-race fatigue. Analysis of GSH concentrations before and after the endurance events demonstrated a significant elevation in the months following the 2013 event, suggesting physiological compensation for increased oxidative stress. However, after a small increase following the 2014 event, GSH concentration quickly returned to baseline levels. It is possible that the combination of sleep deprivation and demanding physical exertion during the 2013 event induced sufficient oxidative stress to cause the excessive fatigue. [ABSTRACT FROM AUTHOR]