External causes of mortality during exercise in school, 1986-1998 / 体力科学

In order to elucidate factors associated with the external causes of mortality during exercise in school from 1986 to 1998, the frequencies and characteristics of mortality were investigated. We used from the booklet“Deaths and injuries under school supervision”published by the National Stadium and School Health Center of Japan. There were 295 deaths (22.7 deaths/year) from 1986 to 1998. The most common cause of mortality was injury (52%), and it also occurred in boys compared with girls in all causes of mortality. In more recent years, the incidence has decreased in injury and drowning, whereas it has increased in heat stroke. The incidence of injury and heat stroke was markedly higher during sports club training, while the incidence of drowning was high during physical education. In injury, most cases occurred during Judo. In drowning, most cases occurred during swimming. In heat stroke, most cases occurred during baseball. Among external causes of mortality in the ICD-10, “struck by thrown, projected or falling object” (W20) in injury, “drowning and submersion while swimming-pool” (W67) in drowning and“exposure to excessive natural heat” (X30) in heat stroke were the most frequent causes. Among the injury, Judo cases most occurred during W20, Rugby and American football cases most occurred during“striking against or bumped into by another person” (W51), and baseball, soccer cases most occurred during“striking against or struck by sports equipment” (W21) . As a result, more attention should be paid to circumstances related to a high incidence of death and the necessity of lecture on the protection and the prevention of external cause of mortality at school.

Seasonal Variation of Trace Element Loss to Sweat during Exercise in Males

Objective: To clarify the seasonal differences of the trace element excretion in sweat, the trace element concentrations in sweat and their loss during exercise were compared between summer and winter.Methods: Sweat samples were collected from ten healthy adult males. Bicycle ergometer exercise was conducted by each subject at a heart rate of 140 beats/min for 1 hour, in summer and in winter. Sweat was collected by the arm bag method.Results: Concentrations of major (Na, K, Ca, and Mg) and trace elements (Zn, Cu, Fe, Ni, Mn, and Cr) in sweat tended to be lower in summer than in winter, and significantly lower concentrations of Mg (p<0.01), Na, Cu, and Mn (p<0.05) were found in summer. The sweat volume in summer (0.90 L) was 1.7-fold larger than that in winter (0.52 L) (p<0.01). The amount of loss of each element to sweat calculated from the concentrations in sweat and sweat volume showed no significant difference between summer and winter.Conclusions: It is suggested that there was no significant difference in the amount of loss of trace elements in sweat due to exercise between summer and winter.

Seasonal variation of trace element loss to sweat during exercise in males

<p><b>OBJECTIVE</b>To clarify the seasonal differences of the trace element excretion in sweat, the trace element concentration in sweat and their loss during exercise were compared between summer and winter.</p><p><b>METHODS</b>Sweat samples were collected from ten healthy adult males. Bicycle ergometer exercise was conducted by each subject at a heart rate of 140 beats/min for 1 hour, in summer and in winter. Sweat was collected by the arm bag method.</p><p><b>RESULTS</b>Concentrations of major (Na, K, Ca, and Mg) and trace elements (Zn, Cu, Fe, Ni, Mn, and Cr) in sweat tended to be lower in summer than in winter, and significantly lower concentrations of Mg (p<0.01), Na, Cu, and Mn (p<0.05) were found in summer. The sweat volume in summer (0.90 L) was 1.7-fold larger than that in winter (0.52 L) (p<0.01). The amount of loss of each element to sweat calculated from the concentrations in sweat and sweat volume showed no significant difference between summer and winter.</p><p><b>CONCLUSIONS</b>It is suggested that there was no significant difference in the amount of loss of trace elements in sweat due to exercise between summer and winter.</p>

Sudden cardiac deaths during exercise in school (1986-1995) / 体力科学

In order to elucidate factors associated with sudden cardiac death during exercise in school from 1986 to 1995, the frequency and characteristics of death were investigated. The authors collected data from the booklet “Deaths and injuries under school supervision” published by the National Stadium and School Health Center of Japan. There were 480 cases of sudden cardiac death during exercise from 1986 to 1995, and boys accounted for 74% of these cases. In more recent years, the incidence per one hundred thousand persons has decreased in elementary and senior high schools ; whereas it has increased in junior high school. Regarding activity at the time of occurrence, 251 cases (52%) occurred during physical education ; 144 cases (30%) during sports club training; and 85 cases (18%) during school events. Incidence during sports club training in elementary school was significantly lower than that in junior and senior high school. Regarding past history, in most case, there was no past history of heart disease. Regarding types of exercise, incidence while running was highest (48%) . Among “running” cases, most occurred during training. Regarding past history, the incidence of cases showing a past history was high for light intensity running, and the incidence of cases without a past history was high during running that involved upper light intensity running. Regarding the stages of running, incidence was markedly higher in the first half of the running period among cases showing a past history, and during training and for light exertion, while the incidence was high in the latter half of the running period among cases without a past history, and also high during timed races and for upper light exertion. Among causes of death, acute heart failure was the most frequent cause. As a result, more attention should be paid to circumstances related to a high incidence of death and the necessity of teaching health care and the prevention of sudden death at school and at home.

CHANGES IN SERUM CHOLINESTERASE AND TRANSAMINASE ACTIVITIES AFTER EXERCISE IN MAN / 体力科学

Changes in serum enzyme activities (GOT, GPT and ChE) were investigated in trained and control subjects both of which were made to perform exercises of three different intensities (mild, moderate and heavy) . It was thought that this study might aid in elucidating the relationship between serum enzyme activities and the blood lactic acid level as an index of hypoxia.<BR>The results are summarized as follows:<BR>1) Both activity levels of the serum enzymes and the concentration of blood lactic acid were higher at rest in the control subjects than in the long distance runners.<BR>2) Activity levels of serum ChE as well as GOT, GPT increased in propotion to the intensity of work.<BR>3) In serum GOT, GPT and ChE activities no statistically significant difference was found between the two groups in all work loads.<BR>4) Relationships between the increase of blood lactic acid concentrations and those of the serum enzyme activities at three minutes after the exercise were all found statistically significant (P<0.001) (with GOT r=0.845, GPT r=0.768 and ChE r= 0.835) .