The principal objective of this paper is basic research on the development of an easy and rapid method to estimate physical fatigue levels. The focus of the research is to determine chronically fatigued conditions at an early stage for the prevention of chronic fatigue. Special attention was given to overtraining as one form of chronic fatigue in this paper. Long-distance runners representatives of a university in Tokyo nominated for Hakone-Ekiden were recruited as subjects. Examinations with informed consent were carried out on a once a month basis during 8 months and included the following; 1) physical characteristics ; body weight and body fat weight, 2) serum-biochemical test ; 6 parameters by the dry-chemistry method and the traditional method, 3) subjective fatigue levels ; the questionnaire of subjective symptom authorized by the Japan association of industrial health and the profile of mood state (POMS) . In this paper, data obtained from 19 male runners attending all 8 examinations were statistically analyzed.
Serum parameters obtained by the dry-chemistry method, an easy and rapid method which provides clinical values on site, showed significant correlations with the traditional method.
No correlation was observed between subjective fatigue scores and serum enzyme activity levels which were used as markers for estimation of physical fatigue levels in this study, however, monthly changes of enzyme levels and fatigue scores from July to August seemed to correlate in almost subjects. In contrast, using data obtained in the entire exprimental period, there was no relationship between the monthly changes of enzyme levels and fatigue scores. The results may indicate that some subjects exhibit gaps between physical fatigue and feelings of fatigue.
The above mentioned results suggest that measurements of serum enzyme activity levels using the dry-chemistry method are a useful indicator for the prevention of overtraining.

Phagocytic cells, polymorphonuclear leucocytes and macrophages, play an important role in non-specific cellular immunity, which is the first line of defense against infectious diseases. The purposes of this study were to clarify the combined effects of forced exercise and sleep disturbance on non-specific cellular immunity in mature rats, and to compare the effects between forced and voluntary exercise. Non-specific cellular immunity represented by the yield of cells from bronchoalveolar lavage and the superoxide-generating capacity of alveolar macrophages was investigated using mature rats.
Male Wistar rats (11 weeks old) were divided into 5 groups:
1) Training group ; exercised on a treadmill at a belt speed of 35 m/min for 15 min/day,
2) Jet Lag group ; disturbance of the sleep cycle by day/night time shifts at 2-week intervals,
3) Training+ Jet Lag (T + J) group ; exercised on a treadmill with sleep disturbance, a model identified by our research group to simulate chronic fatigue, 4) Voluntary group ; housed with running wheels, and 5) Control group ; housed under sedentary conditions.
Body weight and food consumption measured during the experimental period showed coincidental changes. After 6 weeks of the experiment, the rats were sacrificed at the age of 17 weeks. Negative effects on non-specific cellular immunity were observed in the training group, and the rats were also slightly affected by sleep disturbance (Jet Lag group) . These negative effects seemed to be cumulative in the T+J group. In contrast, significant positive effects were observed in the voluntary group.
These results suggest that stress, forced exercise and sleep disturbance negatively affect non-specific cellular immunity, and that voluntary exercise is able to enhance immunity even if it is started after maturation.

Enrolled in our study were 16 seriously handicapped persons (9 males and 7 females) institutionalized in our medical center. They were 20 to 58 years of age (mean 35 yrs). In the previous study, we found they had no evidence, serological or clinical, of osteomalacia but were verified as having significantly low bone mineral density (BMD) at the calcaneus and lumbar vertebrae. Serum levels of 25-OH-vitamin D were low and positively correlated with the lumbar vertebral BMD. Thus we postulated that low BMD was at least partly due to the lack of ultraviolet exposure. In the present study, the lumbar vertebral BMD of the above subjects were measured before and after increasing their exposure to sunlight. We found that mean lumbar BMD increased signigicantly from 770 mg/cm² to 786 mg/cm² (P<0.05, Wilcoxon, paired test). The Z-score also increased significantlyfrom 78 ± 13% to 80 ± 12%(P<0.05, Wilcoxon, paired test).
These findings suggest low BMD could be corrected to some extent by increasing sunlight exposure of institutionalized persons. Former members of farming communities who are retired, handicapped, or otherwise limited to indoor activity, can also recover their BMD and prevent osteoporosis by an increased daily exposure to sunlight.