Credible concepts of malnutrition depend critically on evidence that functional impairment differentiates variation in size from unacceptable abnormality. This paper reviews functional studies on capacity for work, mortality, reproductive outcomes, competitive success, and cultural preferences. Future research priorities should include the comparative significance of simple physical dimensions in distinct ethnic groups for long-term biological and socio-economic outcomes, and the relationships between the biological and cultural significance of variation in physique.
The relationship between physical activity and health-related physical fitness was evaluated in 282 Taiwanese adolescents 12-14 years of age. The subjects were randomly selected from the 7th, 8th and 9th grades in two junior high schools in Taiwan. Physical activity was estimated as total daily energy expenditure and energy expenditure in moderate-to-vigorous physical activity from 24-hour activity records for three days, two week days and one weekend day. Health-related fitness was assessed as the one-mile run (cardiorespiratory endurance), timed sit-ups (abdominal strength and endurance), sit-and-reach (lower back flexibility), and subcutaneous fatness (sum of the triceps, subscapular, suprailiac, and medial calf skinfolds). Physical activity is significantly and positively correlated with one-mile run performance and the sit-and-reach, but not with sit-ups and subcutaneous fatness. Overall, the strength of the relationships between estimated energy expenditure and specific fitness items in the total sample vary from low to moderate, with only 1% to 12% of the variance in fitness variables being explained by estimated energy expenditure. Comparisons of active versus inactive, and fit versus unfit adolescents provide additional insights. The more active (highest quartile) are also more fit in cardiorespiratory endurance and in the sit-and-reach than the less active (lowest quartile), and the more fit in the one-mile run (better time, lowest quartile) and the sit-and-reach (highest quartile) are more active than the less fit in each item, respectively.
Mortality in the Goto archipelago region of the Nagasaki prefecture in Japan is higher than the Japanese average. In this study, we investigated dietary intake, habitual physical activities, systolic and diastolic blood pressure, serum total cholesterol and high-density lipoprotein cholesterol of middle-aged women in the Narao community in the Goto archipelago. We compared these parameters with a Japanese sample, and analyzed the results according to body mass index (BMI) and age. The mean BMI of Narao women was higher than that of the Japanese sample. Serum cholesterol and blood pressure of Narao women correlated with BMI. However, dietary intake and physical activities did not differ between normal- and over-weight Narao women. The higher serum total cholesterol and diastolic blood pressure of Narao women, relative to the Japanese sample, could be explained by the presence of over-weight women in the Narao community. However, dietary and behavioral factors associated with higher BMIs could not be clarified in this cross-sectional study.
To investigate the behavior of mechanomyogram (MMG) and electromyogram (EMG) signals in the time and frequency domains during sustained isometric contraction, MMG and surface EMG were obtained simultaneously from four muscles: upper trapezius (TP), anterior deltoid (DL), biceps brachii (BB), and brachioradialis (BR) of 10 healthy male subjects. Experimental conditions consisted of 27 combinations of 9 postures [3 shoulder angles (SA): 0°, 30°, 60° and 3 elbow angles (EA): 120°, 90°, 60°] and 3 contraction levels: 20%, 40%, and 60% of maximum voluntary contraction (MVC). Subjective evaluations of fatigue were also assessed using the Borg scale at intervals of 60, 30, and 10 sec at 20%, 40%, and 60% MVC tests, respectively. The mean power frequency (MPF) and root mean square (RMS) of both signals were calculated. The current study found clear and significant relationships among physiological and psychological parameters on the one hand and SA and EA on the other. EA's effect on MVC was found to be significant. SA had a highly significant effect on both endurance time and Borg scale. In all experimental conditions, significant correlations were found between the changes in MPF and RMS of EMG in BB with SA and EA (or muscle length). In all four muscles, MMG frequency content was two or three times lower than EMG frequency content. During sustained isometric contraction, the EMG signal showed the well-known shift to lower frequencies (a continuous decrease from onset to completion of the contraction). In contrast, the MMG spectra did not show any shift, although its form changed (generally remaining about constant). Throughout the contraction, increased RMS of EMG was found for all tests, whereas in the MMG signal, a significant progressive increase in RMS was observed only at 20% MVC in all four muscles. This supports the hypothesis that the RMS amplitude of the MMG signal produced during contraction is highly correlated with force production. Possible explanations for this behavioral difference between the MMG and EMG signals are discussed.
The effect of postprandial body posture on digestion and absorption of dietary carbohydrate were examined through breath hydrogen test on 6 female subjects. During the experiment, the participants either sat on a chair or lay on their backs for the first 4 hr (from 08:00 to 12:00) after eating the test breakfast meal. They then remained sedentary on a sofa for 6 hr (12:00 to 18:00). Participants' end alveolar breath samples were collected for 10 hr (every 15 min from 08:00 to 12:30, and then every 30 min until 18:00). The experiment was conducted on two consecutive days using a randomized, crossover study design. The results demonstrated that in the supine position orocecal transit time of the test meal was significantly slower than in the sitting position (260 ± 21 min and 238 ± 20 min, respectively, p<0.01). In addition, afternoon breath hydrogen excretion due to a partial malabsorption of dietary carbohydrate and its fermentation in the colon was significantly larger in the sitting position (144.0 ± 24.1 ppm · hr) than in the supine position (110.0 ± 26.1 ppm · hr, p<0.05). These results support the hypothesis that there was a marked effect of postprandial body posture on the function of the digestive system. The present findings suggest that the postprandial supine position is preferable to the sitting position for the digestion and absorption of dietary carbohydrate.
In this study, we examined the effects of a potent cysteine protease inhibitor, N-(L-3-trans-carboxyoxirane-2-cabonyl)-L-leucine-4-aminobutylamide (E-64a), on bone weight and strength in tail-suspended rats. We first administered a vehicle or 4 or 8 mg/rat of E-64a to rats fed with a low calcium diet for 7 wks to determine effective doses of E-64a on bone resorption in vivo. Femoral cathepsin K-like activity and serum hydroxyproline level in rats fed with a low calcium diet were significantly higher than those in rats fed with a standard diet. The intraperitoneal injection of 8 mg/rat of E-64a to rats decreased their serum calcium and hydroxyproline concentrations after 3 to 6 hrs in parallel with changes in femoral cathepsin K-like activity, while 4 mg/rat of E-64a had weaker effects on these parameters. Based on these results, we injected 8 mg/rat of E-64a to tail-suspended rats twice a day for 2 wks and compared the results with those of treatment with 1 mg/rat of etidronate, a bisphosphonate, twice a week. In tail-suspended rats, femoral weight and strength, assessed by three-point bending test, significantly decreased from Day 5 to 21, while femoral cathepsin K-like activity and serum calcium and hydroxyproline concentrations did not change. E-64a inhibited femoral cathepsin K-like activity in tail-suspended rats, but etidronate did not. E-64a as well as etidronate significantly prevented the suspension-induced declines in bone weight and strength. However, more frequent injection and higher doses were required for E-64a to exhibit significant efficacy of antiresorption, compared with those of etidronate. Our results suggest that a cysteine protease inhibitor could improve suspension-induced osteopenia by inhibiting cathepsin K-like activity in bone; however, it needs several improvements in the effect as a clinical drug.
The observations described in this paper were made during a study of the effects of tropical climate upon Vietnamese and Japanese. We measured rectal and skin temperatures every 10 min for 26 hrs in 6 Vietnamese and 6 Japanese. The experiments have been conducted for 2 hot months, June and July 1999 and 2000 in Hanoi, Vietnam. The ambient temperatures ranged from 33 to 36°C. The results obtained are summarized as follows: 1) Skin temperatures at thigh, forearm and hand during the daytime were significantly higher in the Vietnamese subjects than in the Japanese ones. It would be physiological reactions to warm ambient temperatures, which is advantageous for dissipation of body heat. 2) The average rectal temperature during the daytime is significantly higher in the Vietnamese than in the Japanese, while significantly lower at night. 3) Average range of oscilation of rectal temperature was 1.26°C in the Vietnamese, which was clearly greater than in the Japanese. The higher core temperature, which was actively regulated under warm temperature, seemed of adaptive significance, resulting in the reduction of water consumption like camels in the desert. A greater range of oscillation in tropical Vietnamese people might have ecological significance for efficient acclimatization in the warm environment, suggesting that the setpoint of core temperature could show a greater range of oscillation.
The present study was designed to investigate the effects of clothing skin pressures exerted by two different types of brassieres (a conventional higher skin-pressured brassiere and a newly devised low skin-pressured brassiere) on the autonomic nervous system (ANS) activity. Six healthy young women (22.8 ± 1.4 yrs.) with regular menstrual cycles participated in this study. The ANS activities were assessed by means of heart rate variability power spectral analysis. The skin pressures exerted by the brassieres were measured with an air-pack type contact surface pressure sensor at five different points. The total amount of clothing pressure, and the pressures at the center and the side regions of the brassieres were significantly greater in the high than in the low skin-pressured brassiere (Total 9816.1 ± 269.0 vs. 6436.8 ± 252.4 Pa, P<0.01; Center 2212.1 ± 336.3 vs. 353.8 ± 85.8 Pa, P<0.01; Side 2556.8 ± 316.1 vs. 1747.2 ± 199.2 Pa, P<0.05). Concerning the ANS activity, the Total power, and the very low frequency (VLF) and the high frequency (HF) components were significantly decreased in the high skin-pressured brassiere than those in the low skin-pressured brassiere (Total 531.6 ± 57.3 vs. 770.5 ± 54.2 ms2, P<0.01; VLF 60.7 ± 14.6 vs. 179.2 ± 38.1 ms2, P<0.05; HF 209.5 ± 33.2 vs. 283.2 ± 61.5 ms2, P<0.01). Our data indicate that the higher clothing pressures exerted by a conventional brassiere have a significant negative impact on the ANS activity, which is predominantly attributable to the significant decrease in the parasympathetic as well as the thermoregulatory sympathetic nerve activities. Since the ANS activity plays an important role in modulating the internal environment in the human body, excess clothing pressures caused by constricting types of foundation garments on the body would consequently undermine women's health.
To alleviate worker's thermal discomfort in a moderately hot environment, a new cooling vest was designed and proposed in this paper. To investigate the effect of the cooling vest and to collect the knowledge for the design of comfortable cooling vest, subjective experiments were conducted. Two kinds of cooling vests, the new one and the commercially available one, were used for comparison. The new cooling vest had more insulation and its surface temperature was higher than the commercially available one. Experiments were performed in the climatic chamber where operative temperature was controlled at 30.2°C and relative humidity was at 37% under still air. In addition, experiment without cooling vest was carried out as a control condition. The results obtained in these experiments were as follow: 1) By wearing both types of cooling vest, the whole body thermal sensation was closer to the neutral conditions than those without cooling vest. This effect was estimated to be equal to the 5.7°C decrement of operative temperature. The subjects felt more comfortable with the cooling vest than without it. They felt more thermally acceptable than that without cooling vest. Wearing the cooling vest was useful to decrease the sweating sensation. 2) The local discomfort was observed when the local thermal sensation was "cool"~"cold" with the cooling vest. 3) The new cooling vest kept the skin temperature at chest at about 32.6°C. On the other hand, by wearing the commercially available one, it lowered to about 31.1 °C. By wearing the new cooling vest, there was a tendency that local thermal sensation vote was higher and local comfort sensation vote was more comfortable than those of the condition wearing the commercially available one. It is important for the design of a comfortable cooling garment to prevent over-cool down from the body.