The Annals of physiological anthropology = Seiri Jinruigaku Kenkyukai kaishi最新文献

The aim of this study is to examine the objectivity and reproducibility of intracellular pH threshold (pHT) detected by eye (E), and by regression analysis on linear (L), semilog (SL) and log-log (LL) models. Threshold for inorganic phosphate-to-phosphocreatine ratio (PT) was also examined by three regression analysis. Fifteen males volunteered as subjects. They performed wrist flexion in a ramp protocol of 0.14W/min till exhaustion. Throughout the exercise, 31P-MRS was obtained continuously from wrist flexors. Intracellular pH and phosphate compound in the muscle tissue were monitored as minute-by-minute data. In E, three observers determined pHT subjectively as a work rate just before pH decrement. In three regression analysis, pHT was detected as an intersection of a pair of linear regression lines which was selected statistically or subjectively. pHT detected by four methods showed significant reproducibility between each other, although PT did not. These results provide one of the evidences of threshold behavior of change in pH, and a question of existence of PT in contrast to pHT.

The paper describes the basics of a six-cylinder model of human thermoregulation, written in MS-FORTRAN for use on personal computers. The heat balance equations with respect to the radial coordinate, the initial and boundary conditions, and the controller equations are explained. A complete set of parameter values is given. Emphasis is laid on the problems and status of validation. Therefore conditions and methods, on which a standard set of experimental results (dynamics of 29 core, muscle, subcutaneous and skin temperatures) is based, are explained as well as possible deficiencies both of the experimental and the simulation results. It turned out that within the environmental conditions tested (15-45 degrees C), the model, although simplifying the complex geometry of the human body to six cylinders, gives reliable results, both for steady state and dynamics of body temperature topography.

Threshold of decline in intracellular pH of muscle (pHT) during incremental wrist flexion was studied by 31P-MRS, under two levels of occlusions in which the cuff of the upper arm was inflated to systolic (ES) and diastolic blood pressure (ED), and no occlusion (E). To observe the effect of occlusion per se, intracellular pH at rest under the same two levels of occlusion was measured. Additionally, NIRS was applied to monitor the oxygenation and blood volume of the tissue during the same experimental protocol as the 31P-MRS study. Ten healthy Japanese males participated as subjects in the 31P-MRS study, and three of them in the NIRS study. They performed wrist flexion in incremental loads of 0.14 W/min ramp until voluntary exhaustion. 31P-MRS and NIRS were obtained from wrist flexor muscles. Change in intracellular pH (pH) during wrist flexion showed a threshold behavior even in ischemic conditions, although pH did not decrease at rest under the same two levels of occlusion. This finding indicated that decrease in pH under occlusion is also resulted from exercise induced lactic acidosis. Obtained pHT in ES was smaller than in ED and E significantly, and there was no significant difference between pHT in ED and that in E. From the results of NIRS study, it was confirmed that only venous outflow but not arterial inflow was restricted under an occlusion at a pressure of diastolic blood pressure, but both under an occlusion at a pressure of systolic blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of active recovery after intense muscular exercise was examined by 31P-MRS. Seven healthy males participated in this study, and their right wrist flexor muscles were examined. Each subject flexed the right wrist at 60% of the maximum voluntary contraction (MVC) until the intracellular pH in the wrist flexor muscle decreased to approximately 6.4. This was followed either by active recovery (AR) which consisted of 5, 10, 20, 30 or 40% MVC exercise, and by passive recovery (PR) during a 10-min-recovery period. The intracellular pH (pHi) recovered faster during AR at each condition than during PR. Besides, from the 2nd to the 5th min of the recovery period, the pHi was significantly higher during AR than during PR. The quadratic regression curve of pHi recovery during the 10-min-recovery-period against the % MVC was obtained. The optimal contraction intensity determined from this curve was 8.7% MVC for a 10-min-recovery-period. The optimal levels were determined for another recovery duration within 10 min, and the level decreased with the prolonged recovery duration. These data suggest that mild exercise is an effective maneuver to promote the recovery from intracellular metabolic acidosis, and that the intensity of the recovery exercise should be determined according to the cooling down duration or the resting interval before the subsequent exercise performance.

In patients with spinal cord injury, rectal temperature is difficult to use as body temperature due to impairment such as defecation disturbance. We developed an earphone type device to measure aural canal temperature that can be also used during exercise in patients with spinal cord injury and evaluated its usefulness. The subjects consisted of 11 healthy male students. They exercised for 30 minutes using an ergometer until the heart rate increased to 150-160 bpm. Aural canal temperature, rectal temperature, and non-contact tympanic membrane temperature were measured before, during, and after exercise. This device for the measurement of aural canal temperature was produced by cutting the tip of a commercially available earphone and connecting a thermocouple wire to it. This device is very small and causes no discomfort even during long wearing or inconvenience during exercise. The aural canal temperature obtained in this study was very stable compared with the rectal temperature or non-contact tympanic membrane temperature and thus may be useful for monitoring body temperature.

The present study was designed to compare cardiorespiratory responses of swimmers to swimming and running. Six male trained college swimmers performed maximal work test (progressive method) in flume swimming and treadmill running. VEmax during swimming (128.3 +/- 20.6 l/min) was about 4% lower than during running (133.2 +/- 9.9 l/min). VO2max during swimming (3628 +/- 228 ml/min) was significantly higher than during running (3408 +/- 222 ml/min). HRmax during swimming (191 +/- 8 beats/min) was significantly lower than during running (198 +/- 6 beats/min). VO2 at ventilatory threshold (VT) during swimming (2177 +/- 183 ml/min) was significantly higher than during running (1699 +/- 214 ml/min). %VO2max at VT during swimming (60.1 +/- 4.2%) was significantly about 10% higher than during running (49.8 +/- 4.4%). These results suggest that subjects of this study have specific cardiorespiratory adaptation to swimming from a long period of swim training.

The relationship between body fat indices and cardiovascular risk was analyzed in 97 Japanese women aged 36-72 years. The variables used were anthropometric measures of body fatness, blood lipids and blood pressure. Total adipose tissue weight (TATW) was estimated from bioelectrical impedance measurements. Subcutaneous adipose tissue weight (SATW) was calculated by measuring subcutaneous fat thickness at 14 sites using a skinfold caliper. The indices of body fat distribution were the ratios of waist to hip circumference (WHR) and abdominal to hip circumference (AHR). Blood pressure and serum lipid levels were determined in all subjects after an overnight fast. The correlations among the various body fat indices were high, and all were strongly correlated with WHR and AHR; only % SATW and percentage internal adipose tissue weight (%IATW) were not correlated with WHR and AHR. Significant positive associations were found between WHR, triglycerides and systolic blood pressure (SBP). Negative associations were found between WHR and HDL-cholesterol (HDL-ch.) and the ratio of HDL-ch. to total cholesterol (HDL-ch./T-ch.). On the other hand, significant positive associations were found between AHR, T-ch., LDL-cholesterol, free fatty acid and SBP. A negative association was found between AHR and HDL-ch./T-ch.. Partial correlations were used to determine further associations between cardiovascular risk factors and fat distribution indices. SBP was associated with WHR or AHR after removing the effects of age. Similarly, HDL-ch./T-ch. was associated with WHR or AHR after removing the effects of age and degree of obesity (BMI). These results suggest that the WHR and AHR are equally valid estimates of body fat distribution with respect to their relationship with cardiovascular risk. These relationships occurred independently of age or BMI in Japanese women. These findings emphasize the importance of intra-abdominal obesity as a metabolic risk factor for cardiovascular disease associated with a high WHR and AHR.

The present experiments were carried out to clarify the effects of two different kinds of shoes, i.e., the standard shoes and the mesh shoes, on thermophysiological responses and clothing microclimates (temperature and humidity) in five female students during rest and walking in the field conditions. Main results were summarized as follows: 1) Skin temperatures in instep, sole and leg were kept lower in the mesh shoes than in the standard shoes. 2) Rectal temperature and heart rates were also kept lower in the mesh shoes than in the standard shoes. 3) Questionnaires disclosed that the subjects wearing the mesh shoes felt less damp. These findings were discussed in terms of thermal physiology. The mesh shoes seemed to be more effective for both the dry and wet heat loss from the feet to the surroundings, resulting in the inhibition of increase in the core temperature.

This paper was designed to examine appropriateness of equations for calculating percent body fat from body density. Subjects were 141 boys and 163 girls aged 9-14 years. Body density (Db) was determined by underwater weighing (UW). Residual volume was measured by helium dilution technique (COMP-100, Fukuda Co.). Percent body fat (%fat) was calculated from the formula of Lohman et al. or Brozek et al. The %fat ranged between -0.52% and 44.20% in boys and between 4.94% and 47.44% in girls when the formula of Lohman et al. was used, while the range was 7.00%-45.56% in boys and 11.71%-48.35% in girls when the formula of Brozek et al. was used. In order to examine which formula is more appropriate for the assessment of body composition in boys and girls, %fat values calculated from both formulae were compared. Comparison criterion was essential lipid (boy: 3-5%, girl: 9%). The number of boys whose %fat was 5% or below was 18/141 (12.8%) and the number of girls whose %fat was 10% or below was 19/163 (11.7%) when the formula of Lohman et al. was applied, while the minimum value was 7.00% in boys and 11.71% in girls when the formula of Brozek et al. was utilized. From these results, it is suggested that the formula of Brozek et al. may be more appropriate than the formula of Lohman et al. for the estimation of %fat in boys and girls.