Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5926471 | Respiratory Physiology & Neurobiology | 2011 | 8 Pages |
The accumulation of reactive oxygen species (ROS) is associated with muscular fatigue. The antioxidant N-acetylcysteine (NAC) can extend time to fatigue (TTF), but the effect appears to be exercise intensity dependent. The purpose of this study was to determine the effects of an acute oral dose of NAC on time to fatigue (TTF), critical power (CP), Wâ² (curvature constant), VËO2 kinetics and muscle EMG during cycling exercise. Male (n = 7) subjects performed four tests at power outputs corresponding to 80, 90, 100, and 110% of the peak power output achieved during the incremental test (Pmax) under NAC and placebo (PLA) conditions. TTF was increased only in the 80% Pmax trial (p = 0.033). CP was higher with NAC (NAC: 232 ± 28 W versus PLA: 226 ± 31 W; p = 0.032), but Wâ² tended to decrease (NAC: 15.5 ± 3.8 kJ versus Wâ²: 16.4 ± 4.5 kJ; p = 0.10). The change in Wâ² was negatively related to the change in CP (r = â0.96). MdPF and RMS of EMG tended to change less with NAC. There were no significant differences in VËO2 kinetics. These results demonstrate that oral NAC was successful in extending time to fatigue at 80% Pmax but not at higher work rates.