We investigated the performance of vegetative systems of the body, and gas exchange in the implementation of one athlete (master of skiing, 27 years, MaxVO2 = 67 ml/min/kg) during 6 hours ultra-marathon race in a closed stadium at an average speed of 2.7 m/s. Continuous monitoring of heart rate was carried out using the heart rate monitor Polar RS 800. During the first hour and then for 20-30 minutes each hour gas analysis was performed with Metamaxdevice (Germany), mounted on the test subject during all the time of the race. Before and after the passages of the measured interval distance blood lactate content was measured. These data demonstrate a number of features that accompany fatigue in the final stretches a distance: reduction of body economy, which is to increase heart rate and oxygen cost of work; activation of anaerobic-glycolitic energy production mechanism, the intensification of respiratory function. Along with this, the methods of correlation and regression analysis revealed changes (increase or decrease) the relationship between the functions depending on whether the body is in the initial stage of the physical load, sustainable high performance or in either a state of extreme fatigue. These results suggest the interference effects of the central and tissue mechanisms of fatigue in the organization of the oxygen transport function of the body. Apparently, in the case of ultra-marathon run, that is, long-term work of moderate power, the main limiting factor is not the energy of the body, and the autonomic software.