RELATIONSHIP BETWEEN DAILY STEPS AND PHYSICAL FITNESS IN COMMUNITY-DWELLING ELDERY / 体力科学

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.

EXISTENCE IN SUBJECTS OF LOW PLASMA TRIIODOTHYRONINE CORRELATED WITH POST-ABSORPTIVE RESTING METABOLISM / 体力科学

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 VO₂ 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.

REAPPEARANCE TEST OF THE POST-ABSORPTIVE RESTING METABOLIC RATE IN YOUNG JAPANESE FEMALES / 体力科学

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.

Comparative study of total energy expenditure in japanese men using doubly labeled water method against activity record, heart rate monitoring, and accelerometer methods / 体力科学

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.