A study for prevention of chronic fatigue Part 1. Effects of endurance running during one month on blood properties and subjective fatigue.

The principal objective of this paper is basic research on the development of methods for the prevention of chronic fatigue. Overtraining was paid special attention to as one of the types of chronic fatigue condition. Six healthy male participants in a distance-running competition were recruited and used as subjects for this study with informed consent for all examinations. Subjects, that is, participants in the competition, tried to achieve their objective maximum running distance designated before the competition during one month, while in the same period performing their routine work duties. It was reported that the competition caused participants to exhibit an overtrained condition. In this paper, effects of endurance running during one month on blood properties and the fatigue level felt by the subject (subjective fatigue) were studied.Examinations carried out in this research were as follows; 1) physical examination was conducted 3 times during the study; 1 week before the competition, immediately before and 3 weeks after the end of the competition, 2) blood sampling was conducted 4 times; prior to the competition, 1 week after the beginning of and immediately before the end of the competition, and about 3 weeks after the competition, 3) subjective fatigue levels were monitored 8 times; 1 week before and one time in every week during the competition, and 1 week and again 3 weeks after the competition.Immediately before the end of the competition, when subjects might be expected to exhibit the overtrained condition, minor influences on fatigue levels were found. However, effects of the endurance run seemed to remain more than 3 weeks after the competition as indicated by changes of the population of white blood cells and blood hormone levels.The above mentioned results suggest that it is important to determine signs of overtraining at an early stage. To determine overtraining at an early stage, norepinephrine, testosterone and the ratio of testosterone to cortisol may be the most useful indices. These, as well as the element of "drowsiness and dullness" in the questionnaire on subjective symptoms of fatigue authorized by the Japan Association of Industrial Health and the elements of "anger", "fatigue", and "confusion" in the Profile of Mood State (POMS) questionnaire are thought to be the most important subjective indices.