抄録
The purpose of this study was to evaluate the relationship between the mental fatigue and the strength of physical exercise by event-related potentials (ERPs). Ten healthy college students (mean age: 20 years old) performed two kinds of multi steps exercise loading tests (hard test and soft test) using a treadmill. The loading strength was increased stepwisely until the heart rate of the subjects reached 90% of maximum in the hard test, and that was increased until the heart rate reached 70% of maximum in the soft test. In this study, audito EPRs and lactic acid in blood were adopted as mental fatigue and physical fatigue, respectively. Audito EPRs and the concentration of lactic acid in blood were measured just before and after the exercise in these tests. After these measurements, these parameters, were obtained every one hour for three hours. The latency of P300 in auditory ERPs was prolonged and the amplitude of P300 was decreased by the exercise loading tests. But, hard test and soft test differed each other in recovering patterns of the latency and the amplitude of P300. These results suggest that physical exercise can cause various levels of mental fatigue depending on the strength of physical exercise. However, the recovering patterns of the concentration of lactic acid in blood did not always coincide with recovering patterns of the latency and the amplitude of P300. The level of mental fatigue may not well related with the quantity of fatigue-products accompanied with a physical exercise. [Jpn J Physiol 54 Suppl:S239 (2004)]
