ABSTRACT
This prospective study was designed to clarify the association between the incidence of falls and physical fitness in healthy community-dwelling elderly people without history of fall-related injuries within 1-5 years before the baseline assessment. Six hundred and one elderly subjects aged 60-79 years who lived independently participated in baseline assessments from March 2002 to March 2004, and were followed up for one year to detect falling. Demographic items (age and sex), chronic disease, self-rated health, difficulty in performing any activity, tendency to stay at home, body mass index (BMI), %vital capacity, handgrip and knee extension strength, stepping rate, one-leg standing with eyes opened, trunk flexion at sitting position, maximum walking speed, instrumental activity of daily living (IADL), and General Health Questionnaire (GHQ30) were assessed at baseline. Four hundred and eighty-one participants (80.0%) completed the 1-year follow-up.The fall incidence was 13.1%. In men, fallers had lower BMI and decreased maximum walking speed, however, neither showed significant odds ratio (OR) for fall. In women, fallers had lower knee extension strength and the ratio of weak side to strong side (WS/SS ratio) in knee extension strength compared to non-fallers. The age-adjusted OR for fallers in the lowest quartile (knee extension strength＜0.681kg/BW) was 3.07 (95%CI : 1.02-9.22) compared to highest quartile (＞0.980 kg/BW), while the multiple-adjusted OR was not significant (OR＝2.88, 95%CI : 0.94-8.79). However, the multiple-adjusted OR for fallers in the lowest quartile of the WS/SS ratio in knee extension strength (＜0.771) was 4.49 (95%CI : 1.40-14.37) compared to highest quartile (＞0.947).As for conclusion, without history of fall-related injuries, only a weak association between falls and physical fitness was observed in men. In women, the unbalanced knee extension strength was associated with falls. The WS/SS ratio in knee extension strength might be a key factor in predicting falls in women.
ABSTRACT
There have so far been no studies examining the physical fitness and physical activity (PA), measured using objective measures, in homebound elderly people. The purpose of this study was to examine physical fitness levels and PA patterns and evaluate their relationships in homebound elderly people. In 2004, a total of 3964 community-dwelling elderly aged 65 years and over participated in a base line survey. The subject data were directly collected by in-home interviewer. Subjects were defined as being homebound if they went outdoors less than once a week. However, the subjects who could not go out without assistance due to sickness and/or disability were excluded from the analysis. In 2005, 38 homebound (22 men, 16 women) and 70 non-homebound (33 men, 37 women) older adults who participated in the base line survey were selected. Measurements of physical fitness levels and PA patterns measured using an accelerometer, were taken in 2005. The total steps per day did not significantly differ between homebound and non-homebound men and women. The time spent in 1.8 METs activity (corresponding to activity level 1 of the accelerometer) was significantly higher in women than in men for non-homebound and homebound, respectively. The time spent in lower-, moderate-, and high-intensity PA did not significantly differ between homebound and non-homebound men and women, respectively. Handgrip strength, knee extensor strength, leg extensor power, stepping and maximum walking speed were significantly higher in non-homebound than in homebound men and women. These results suggest that the physical fitness levels of homebound were lower than those of non-homebound, but no difference was observed in the PA levels between homebound and non-homebound.
ABSTRACT
The purpose of this study was to examine the association between the pedometer-determined steps per day and physical fitness in order to evaluate the usefulness of the pedometer-determined physical activity to help individuals meet the recommended exercise target level of the Ministry of Health, Labour and Welfare (MHLW). The subjects consisted of 222 men and 172 women aged 71 years in community-dwelling elderly. The subjects wore a pedometer for 7 consecutive days to measure daily steps. The functional capacity was assessed based on the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC) and self-reported performance of tasks (stair-climbing and chair-rising). Physical fitness tests included handgrip strength, knee extensor strength, leg extensor power, stepping, one-leg standing time with eyes open and maximal walking speed at 10 m. The men and women took on average 6,561±2,907 and 6,329±2,451 steps/day, respectively. Our subjects seemed to be highly functioning elderly, because the total scores of TMIG-IC (maximum : 13 scores) were on average 12 for men and women. The average of steps/day was significantly correlated with stair-climbing, chair-rising and knee extensor strength in men and women, and with body weight, body mass index (BMI), percent body fat (%Fat) and leg extensor power in women. The BMI and %Fat levels were significantly lower while the handgrip strength and knee extensor strength were significantly higher in women who attained to the level of the pedometer-determined physical activity as recommended by the MHLW.The present study suggests that both men and women who take a lot of steps on a daily basis tend to demonstrate excellent leg strength and thus have a good ability to perform the tasks of daily living. In addition, the degree of obesity tends to be lower in women who regularly take a lot of steps. In addition, the number of daily steps taken has been recognized to be linked to gender, and such a link has also been suggested to be stronger in women than in men.
ABSTRACT
The purpose of present study was to examine validity of accelerometer (Lifecorder ; LC) and to assess the free-living physical activity (PA) in Japanese elementary school students used by LC method. Firstly, to examine validity of LC, twelve children, aged 11.2±1.0 years, were measured total energy expenditure (TEE) by doubly labeled water method and resting energy expenditure (REE) by the expired gas analysis. Physical activity energy expenditure (PAEE) is calculated as 0.9 TEE minus REE. At the same time, PA was evaluated by both daily walk count (WC) and vigorous activity time (LC7-9) using LC method. PAEE per 1 kg body weight significantly correlated with WC (r=0.785, p<0.005) and LC7-9 (r=0.828, p<0.001). Secondly, 140 boys and 167 girls, aged 8-11 years were measured PA by LC method. WC and LC7-9 each were 13000-18000 counts and 16-32 minutes in week-day, and 8000-12500 counts and 8-18 minutes in week-end. PA analyzed by MANOVA were significantly higher in boys than in girls, and lower in week-end than in week-day, and decreased in proportion as grade. Present study suggests that LC method is a good measure of PA in free-living condition for elementary school students.
ABSTRACT
The purposes of this study were to investigate the relationships between physical activity variables and physical fitness, and between amount and intensity of physical activity in children and adolescents. Subjects were divided into two groups : 178 children (99 boys aged 9.8±0.6 and 79 girls aged 9.7±0.6) who had not reached the age of peak height velocity (PHV), and 336 adolescents (141 boys aged 15.0±1.1 and 195 girls aged 15.3±1.2) who had reached the age of PHV. Physical activity level (PAL : total energy expenditure/basal metabolic rate) which indicates the amount of physical activity, and time engaged in each of physical activity intensity (light, moderate and vigorous), which indicates the intensity of physical activity were estimated from uni-axial accelerometer. Physical activity was monitored for 3 consecutives days : 2 weekday and 1 weekend day. Moreover, physical fitness test suggested by the Ministry of Education, Culture, Sports, Science and Technology was applied. Results of this study showed that PAL was closely related to physical fitness in children, while time engaged in vigorous activity was more related to physical fitness in adolescents. On the other hand, time engaged in light and moderate activity was closely associated with PAL in younger girls, whereas in younger boys, PAL was closely related to time engaged in moderate and vigorous activity. However, time engaged in moderate activity was more related to PAL in the adolescent group. These results suggest that the relationship between physical activity variables and physical fitness and between amount and intensity of physical activity might vary according to the growth development of boys and girls respectively.
ABSTRACT
The purpose of this study was to examine the effects of walking 10,000 steps/day on the body composition, blood pressure, blood biochemical parameters and physical fitness. Sixty-one women, aged 56.0±5.3 yrs (mean±SD), participated in a hyperlipemia prevention program. The length of the program was 90-min and it was performed one time per week for 3 months. The program consisted of stretching and aerobic exercise (cycle exercise, walking or aerobic rhythmic gymnastics). The participants were asked to walk 10,000 steps/day or more during the program. The number of steps and physical activity (PA) were monitored using a single-axis accelerometer during the program. PA was categorized into three activity levels, namely light (L), moderate (M) and vigorous (V) PA. After 3 months in the program, the participants were divided into two groups according to the average number of steps taken daily during the program : one group (GA) walked more than 10,000 steps/day, while the other (GB) walked below 10,000 steps/day. The time spent in LPA, MPA and VPA in GA were significantly longer than in GB (LPA : 79.4±19.2 min VS 58.2±10.0 min, MPA : 38.5±9.6 min VS 21.6±6.1 min, VPA : 6.3±4.9 min VS 2.6±2.0 min, p<0.001). Decreases in the percent body fat (p<0.001), body fat mass (p<0.001), fasting glucose (p<0.001), hemoglobin A1c (p=0.026), and triglyceride (p=0.036) and an improved performance when balancing on one leg while standing with eyes closed (p=0.027) were found respectively after the program for GA. These findings indicated that GA affected the percent body fat (p=0.036), body fat mass (p=0.040) and fasting glucose (p=0.009). According to a stepwise multiple regression analysis, the time spent in MPA showed a significantly negative correlation with the change in the body fat mass (p=0.025), and the change in the body fat mass showed a significantly positive correlation with the change in the fasting glucose (p<0.001), hemoglobin A1c (p=0.002) and triglyceride (p<0.001). We thus concluded that walking 10,000 steps/day resulted in an increased amount of time spent in MPA, and thus leading to decrease in the amount of body fat. This decrease in body fat is also considered to contribute to improvement in the coronary risk factor profiles.
ABSTRACT
The purpose of this study was to investigate the effect of changes in post-absorptive resting metabolism (PARM) on plasma triiodothyronine (T3) levels under a prescribed diet. The subjects were 31 sedentary female college students (19.9±0.9 yrs). Subjects stayed in a metabolic ward at the National Institute of Health and Nutrition for 18 days. PARM was measured 4 times during the experimental period. Additionally, blood was collected 4 times during the experimental period, and general health care including the measurement of thyroxin by blood biochemical examination was carried out. Subjects were divided into three groups (n=26, n=4, n=1), two of which were analyzed for this study. The two groups were divided according to thyroid function: Group N (n=26) included subjects in which T3 was judged to be within the normal range during the experimental period; Group L (n=4) included subjects for whom T3 was not normal during the study period, and was judged to be under the normal range at least once. The remaining 1 subject had a T3 judged to be over the normal range.For Group N, several parameters decreased significantly during the course of the experiment: weight was 51.5±4.97 vs. 50.8±4.3 kg (p<0.01); T3 was 1.16±0.19 vs. 1.01±0.12 ng/ml (p<0.01); and PARM was 3.1±0.2 vs. 2.9±0.2 ml/min/kg (p<0.05). For Group L, several parameters also decreased significantly during the course of the experiment: weight was 53.6±4.9 vs. 52.6±4.5 kg (p<0.01); T3 was 0.94±0.15 vs. 0.75±0.07 ng/ml (p<0.01); and PARM was 2.9±0.2 vs. 2.7±0.1 ml/min/kg (p<0.05). The average PARM of Group N was significantly higher than that of Group L (7.0%). PARM during the luteal phase of the menstrual cycle was significantly higher than during the menstrual phase (3.5 %), in subjects for whom the phases of the menstrual cycle were distinguishable (n=13).According to the 2005 Dietary Reference Intakes (DRIs) for Japanese, the basal metabolic rate (BMR) is calculated at 23.6 kcal/kg body weight/day, or 3.27 ml/min/kg translated for VO<sub>2</sub> for women within the 18~29 year age group. However, the values calculated from the measurements of this research study were approximately 9.5% lower for Group N and 15.8% lower for Group L than that of the DRIs.Future investigation is required to explain the reasons for the difference in PARM between this study and that of previous ones.
ABSTRACT
The purpose of this study was to assess the validity of activity record (AR), accelerometer (AC) and heart rate (HR) methods in comparison with the doubly-labeled water (DLW) method as the criterion measure of total energy expenditure (TEE) in high school students undergoing vigorous activities. Twelve baseball players in Japanese high school (16.5±0.5 yrs) were monitored for seven consecutive days. TEE values obtained over a 3-day-period by AR, AC and HR were simultaneously validated against TEE measured by DLW over a 7-day-period. TEE value measured by DLW was 4922±391 kcal/day. The Physical activity level (PAL=TEE/BMR (basal metabolic rate)) was 2.66±0.14. TEE estimated by AR, AC and HR was significantly different from DLW, with mean differences of -13.9±6.5%, 35.3±3.6% and 31.6±23.9%, respectively. However, TEE estimated by AC and AR significantly correlated with that measured by DLW (r=0.73, r=0.70, p<0.05, respectively). The limits of agreement between DLW and AR, AC and HR were from -1350 kcal/d to -21 kcal/d, -2293 kcal/d to -1192 kcal/d, and 3875 kcal/d to -797 kcal/d respectively. AC was superior to the other methods. However, the limits of agreement in AR were similar to AC. These data suggest that on accuracy and precision, AR would be superior to the other two for predicting TEE in high school students undergoing vigorous activities. However, AC has the advantages being able to examine patterns of activity over long periods of time without interfering with normal movement and the ability to store data continuously over long periods of time. Therefore, it was suggested that, simultaneously, the AR and AC methods are accurate predictors of TEE and patterns of activity while undergoing sports vigorous activities.
ABSTRACT
The purpose of this study was to examine the effects of long-term habitual exercise on daily total energy expenditure (TEE) and its components, body composition and maximal oxygen uptake (VO<sub>2</sub>max) in middle-aged Japanese women. Twenty-eight subjects aged 39 to 58 years were assigned either to a nonhabitual exercise group (Control ; n=12) or a habitual exercise group (Exercise ; n=16). TEE, physical activity level (PAL) and the daily physical activity energy expenditure (PAEE) were assessed by doubly labeled water (DLW) method. The exercise-induced energy expenditure (ExEE) and nonexercise-induced energy expenditure (NExEE) were evaluated based on the activity record investigation conducted simultaneously during the DLW measurement period. The result follows that TEE was significantly (p<0.01) higher in the Exercise group (2520 kcal · day<sup>-1</sup>) than in the Control group (1921 kcal · day<sup>-1</sup>). There was no significant difference in basal metabolic rate between the groups. PAEE and ExEE were significantly higher in the Exercise group than in the Control group (p<0.01). Habitual exercise induced an increase in TEE without resulting in a compensatory reduction of NExEE. The percentage body fat (fat%) was significantly lower in the Exercise group (25.5%) than in the Control group (30.9%). VO<sub>2</sub>max was higher in the Exercise group (1788 ml · min<sup>-1</sup>) than in the Control group (1417 ml. min<sup>-1</sup>). After correction for body weight, fat% was negatively associated with TEE (p<0.01), PAEE (p<0.01) and ExEE (p=0.05), while VO<sub>2</sub>max was positively associated with TEE (p<0.05), PAL (p<0.05), PAEE (p<0.05) and ExEE (p<0.01). These results suggest that habitual exercise is associated with the increase of TEE, the improvement of body composition and VO<sub>2</sub>max. The improvement of VO<sub>2</sub>max was mainly caused by the increase in ExEE, indicating that the exercise intensity is important to the improvement of cardiorespiratory endurance fitness.
ABSTRACT
The purpose of this study was to investigate the reappearance of the post-absorptive resting metabolic rate (PARM) during a prescribed diet. The subjects were 10 sedentary female college students (20.1±0.7yrs) . Thyroid function was judged in all of them to be within a normal range. Subjects stayed in a metabolic ward at the National Institute of Health and Nutrition for 18 days. The post-absorptive resting metabolic rate was measured 4 times during the experimental period. Moreover, blood was collected five times, and general health care including the measurement of thyroxin by blood biochemical examination was carried out. As for the actual metabolic measurements, a high reappearance was confirmed by the intra-individual coefficient of variation (CV) of the post-absorptive resting metabolic rate (3.5±1.8%) and the inter-individual CV (7.2%) . The smallest CV was the standard value of PARM/body surface area, followed by PARM/body weight, PARM/LBM, and PARM/urine creatinine. On the other hand, weight (50.8±4.9 vs 50.3±4.6 kg ; p<0.01), hemoglobin concentration (13.7 ± 0.5 vs 12.8±0.5g/dl ; p<0.05), serum total cholesterol level (194±41 vs 175 ± 37 mg/dl ; p<0.05) and post-absorptive resting oxygen uptake (0.149±0.01 vs 0.142±0.011/min ; p<0.01) decreased significantly during the experiment. According to the Japanese Recommended Dietary Allowances (RDAs) (1999), basal metabolic rate (BMR) was calculated at 1, 210 kcal/day or 23.6 kcal/kg body weight/day for women within the 18-29 year age group. But the results (the mean of all measurements) of this research suggested that this value was 1, 033 ± 79 kcal/day, or 20.7 ± 2.0 kcal/kg body weight/day based on the method of Weir ; and was approximately 10% lower than RDAs. Future investigation is required to explain the reasons for the difference in BMR between this study and that of previous ones.
ABSTRACT
This study examined total energy expenditure (TEE) of Japanese firefighters under normal working conditions, and also evaluated several field methods for measuring TEE in comparison with the doubly labeled water (DLW) method. Ten male subjects belonging to Tokyo metropolitan firefighters departments, aged 30.0±2.8 yrs (mean±SD), were monitored for five consecutive days. While TEE was assessed by an accelerometer (AC) and activity records (AR) in additoin to DLW, energy intake (El) was evaluated by dietary record. There were three emergency calls over the assessment period, but no real operation of fire suppression. TEE obtained by the DLW method (4009±611 kcal/d) was significantly higher than that estimated by AC (2531±186 kcal/d) or AR (3704±476kcal/d) ; but significantly correlated with AR (r=0.876, p<0.01) . El (3539±286 kcal/d) showed no significant relationship with DLW. These results suggest that compared with AC, AR would be more feasible for estimating TEE of firefighters, who perform special activities carrying heavy equipment. The mean value of physical activity level (PAL) (2.2±0.3) indicates that firefighters can be categorized as heavy workers like soldiers or policemen.
ABSTRACT
Daily energy expenditure has been measured by the physical activity recording and/or the questionnaire method. Recently, the accelerometer or pedometer is used to measure daily energy expenditure. The purpose of this study was to examine validity of the pedometer with accelerometer and to compare the daily physical activity between young and older Japanese. To examine validity of the pedometer, 10 young subjects worn the pedometer (Lifecorder) on the waist and then performed the walking test. Energy expenditure was measured by the expired gas analysis during the test. Fourtythree young and 54 older subjects worn the Lifecorder on the waist during free-living condition for 14 days. The intensity of Lifecorder had a high correlation with the physical activity intensity (METs) (r=0.958, P<0.001) . In the free-living condition, daily energy expenditure was 2171±305 kcal in young and 1617±196kcal in older (P<0.001) . Total step in young was significantly higher than older (young: 9490±2359 steps ; older: 6071±2804 steps, P<0.001) . There was no significant difference in the duration of physical activities at the Lifecorder intensity 1 such as desk working, watching TV sitting on a sofa and driving a car. However, the duration more than the intensity 2 corresponding to 2.2 METs in young subjects was longer than that in older (P<0.001) . We concluded that in older subjects, not only amounts of daily energy expenditure but also intensities of daily living were lower compared to the young subjects.
ABSTRACT
The purpose of this study was to examine total energy expenditure (TEE) in Japanese men under free-living conditions using various field methods, and compare these methods with the doubly labeled water method (DLW) . Ten Japanese men, aged 24.2±1.8 (mean±SD) yrs, were studied for 14 consecutive days. TEE was assessed by DLW, activity record method (AR ; using relative metabolic rate and calculated basal metabolic rate), heart rate monitoring methods (Two-line and FLEX-HR methods), and accelerometer method (AC) . Energy intake (EI) was also evaluated over the same period. Although TEE estimated by AR (2730±139 kcal⋅day<SUP>-1</SUP>), Two-line (2925±433 kcal⋅day<SUP>-1</SUP>), and FLEX-HR (2949±506 kcal⋅day<SUP>-1</SUP>) did not differ significantly from the TEE determined by DLW (2910±524 kcal⋅day<SUP>-1</SUP>), there was no significant relationship between each of these methods and DLW. In addition, El (2963±482 kcal⋅day<SUP>-1</SUP>) and TEE determined by DLW were similar, and there was a significant correlation (r=0.809, P<0.01) . Compared with DLW, AC (2697±541 kcal⋅day<SUP>-1</SUP>) underestimated TEE at the group level ; however, AC was the only method to show a significant correlation with DLW (r=0.871, P<0.001) . Therefore, it seems possible that AC would accurately estimate TEE at the individual level by improving both the instrument and its methodology.
ABSTRACT
This study was designed to evaluate effects of long-term swimming training on maximal aerobic capacity and sernm lipid and lipoprotein profile of postmenopausal women. In the first study, 12 swimming-trained postmenopausal women (age: 58±3 yrs, BMI : 22± 2 kg/m<SUP>2</SUP>, training distance : 3.6±1.6 km/wk, mean±SD) were compared cross-sectionally with 50 age-matched untrained women (58±5 yrs, 23±2 kg m<SUP>2</SUP>) . Swimming-trained women had higher maximal oxygen uptake (Vo2max) than untrained (34± 5 vs. 30± 5 ml/kg/min, P<0.05) . Serum total- and HDL-cholesterol (T-C and HDL-C) and triglyceride (TG) concentrations in swimmers were similar to those in untrained (T-C: 232±23 vs. 220±44 mg/dl, HDL-C : 69±15 vs. 72±17 mg/dl, TG : 83±21 vs. 99±67 mg/dl) . On the other hand, swimmers had higher serum LDL-cholesterol concentrations (LDL-C) than untrained women (161±28 vs. 138±25 mg/dl, P<0.05) . The second study was conducted to test the effects of a 2-year swimming program on Vo2max and serum lipid and lipoprotein concentrations of postmenopausal untrained women. After the swimming program 10 trained women (age : 59±7 yrs, BMI : 23±3 kg/m<SUP>2</SUP>, Vo2max : 30± 3 mlikg/min at baseline, training condition : one hour session, frequency: 1.5±0.4 times/week during the program) and 12 untrained women (60± 5 yrs, 23± 3 kg/m<SUP>2</SUP>, 29± 5 ml/kg/min at baseline) were retested. No change in BMI was observed in the two groups. At the 2-year follow-up, the trained women increased Vo2max (34± 5 ml/kg/min, P<0.05), whereas no change in Vo2max was observed in the untrained women (30± 5 ml/kg/min) . No changes occurred in concentrations of T-C (Trained : 238±25 233±21 mg/dl, Untrained : 236±20 236±32mg/dl), HDL-C (Trained : 70 ± 15→74 ± 16 mg/dl, Untrained: 69 ± 15→69 ± 14 mg/dl), LDL-C (Trained : 150 ±29 144±27mg/dl, Untrained : 144±15→145±23mg/dl), and TG (Trained : 90±32 74±25 mg/dl, Untrained : 115±81 106±52mg/dl) . These results suggest that although a long-term swimming program can increase maximal aerobic capacity, favorable changes in sernm lipids or lipoproteins can not be expected for postmenopausal women.
ABSTRACT
In this study, we investigated the effects of a 2-year swimming program on suppressing bone loss in postmenopausal women. There were 22 subjects who participated in the swimming program (mean age 59.5 yr) and 19 controls (mean age 59.3 yr) . The program consisted of one-hour exercise sessions ; and the swimmers had on average 1.5 sessions per week. BMD at the lumbar spine (L2-L4) and proximal femur (neck, trochanter, and Ward's triangle) were measured by dual X-ray absorptiometry (DXA) ; and leg extensor power was measured using a dynamic leg extensor power rig. All the measurements were taken at baseline, 1 and 2 years. Height, weight, calcium intake and daily activity profiles were similar between the two groups, and these changed little throughout the experiment. In regard to leg extensor power, the swimming group had a significant increase at 1 and 2 years. At 2 year, the swimming group demonstrated 4.4%, 5.7% and 3.4% increases in BMD at the femoral neck, trochanter and Ward's triangle, respectively, while the control group showed slight decreases of BMD at the femoral neck (-0.2%) and Ward's triangle (-1.4%) . Significant differences in the rate of change in BMD at each site were observed between the two groups. The swimming group showed a decrease in lumbar spine BMD, as did the control group and the rate of the decline did not differ between the two groups. This study suggests that a 2-year swimming program for postmenopausal women can induce the beneficial effects of retarding bone loss at the proximal femur site and increasing leg extensor power.
ABSTRACT
Using atomic absorption spectrophotometry, we measured serum mineral (Fe, Cu, Z n, Mg, Ca, K, Na) concentrations in blood of male athletes participating in a triathlon competition held at Nakajima, Ehime in 1989. The athletes were divided into a young group (n=9, 24.2±3.6 yr) and a middle-aged group (n=9, 49.3±4.4 yr) . Blood samples were taken on the day before the competition, at the finish, on the following day and for eight days after.<BR>Immediately after the race, the concentrations of iron, calcium and potassium were increased significantly in sera taken from both groups, and those of copper and zinc were found to be increased only in the young group. In the middle-aged group, serum magnesium and sodium concentrations were decreased significantly. On the day after the race, most of the serum mineral concentrations had returned to values similar to those measured before the race, although the serum sodium concentration in the middle-aged group was still below the previous value, and this low level persisted for eight days after the race in both groups.<BR>Noticeable differences between the young and middle-aged groups were that recovery of increased iron concentration in serum tended to be prolonged in the middle-aged group, and the concentrations of serum copper and zinc were higher than those in the young group throughout the measurement period, with only small changes evident before and after the race. By contrast, serum potassium concentration in the middle-aged group was lower than in the young group throughout the measurement period.