ABSTRACT
<b>PURPOSE</b> : The purpose of this study was to clarify the effects of prolonged expiration (PE) on respiratory and cardiovascular responses and autonomic nervous activity during the exercise.<b>METHODS</b> : Twenty-five healthy men (22±1years) were classified according to the breathing mode during the exercise : 2-second inspiration and 4-second expiration in 1 : 2 group, 3-second inspiration and 3-second expiration in 1 : 1 group and normal breathing in control group. The 6-minute exercise was performed at anaerobic threshold (AT) and 60%AT using a cycle ergometer as an exercise protocol. Respiratory rate (RR) and tidal volume (TV) were measured by the expired gas analysis. The power of low- (LF) and high-frequency components (HF) was analyzed from a Holter electrocardiogram to assess the heart rate variability. <b>RESULTS</b> : RR and LF/HF were significantly lower, TV and HF were significantly higher during the exercise of 60%AT and AT in the 1 : 1 and 1 : 2 groups than in the control group (P<0.05 or P<0.01). The increase of HR was significantly lower and that of HF was significantly higher during the exercise at 60%AT in the 1 : 2 group than in the 1 : 1 group (P<0.05). <b>CONCLUSION</b> : PE activated the parasympathetic nervous activity and consequently restrained an excessive increase of HR during the exercise at 60%AT.
ABSTRACT
A study was conducted to assess gender differences of body fat distribution (i. e., total body fat mass, subcutaneous fat mass, and internal fat mass) in a homogeneous group of Japanese children. Body composition was estimated in 141 boys and 139 girls (aged 3-6 yr) using bioelectrical impedance analysis (BIA) . All subjects were apparently healthy. Determinations of impedance were made using a four-terminal impedance analyzer (TP-95 K, Toyo Physical, Inc., Fukuoka) . The lean body mass (LBM) was calculated using the equation of Kushuner et al. (1992) and Goran et al. (1993) . Total body fat mass (TFM) was calculated as the difference between body weight and LBM. The subcutaneous fat mass (SFM) was calculated using a modification of the equation derived by Skerjl et al. (1953) . The internal fat mass (IFM) was calculated as the difference between TFM and SFM. From ages 3 through 6 years, the mean LBM increased with age in boys and girls, but showed no significant gender differences. There were also no obvious gender differences in TFM and IFM within the same age range. Percentage body fat decreased in both sexes until the age of approximately 5-yr, and then increased again slightly at 6 yr, although it showed no significant differences between the sexes. The gender-specific pattern of fat accumulation during childhood was characterized by an almost steady increase of SFM in girls. These differences were independent of gender differences in physical characteristics.
ABSTRACT
In 176 Japanese women aged 20-79, participating in a health assessment programme, we studied the associations between several metabolic features and the type of obesity based on body mass index and waist to hip circumference ratio. We propose the existence of three types of obesity based on BMI and WHR : Type-I, obese women who have a high BMI and a low WHR, Type-II, obese women who have a low BMI and a high WHR, and Type-III, obese women who have both a high BMI and a high WHR. Age was categorized into three levels for all analyses (≤49, 50 - 59, and ≥60 yr) . There was no significant association of WHR with any metabolic variable after adjustment for the effects of the BMI in any group. The results of the present study show that the amount of body fat is in itself more important than the WHR. Where p values were significant, levels of metabolic risk factors for disease increased across the tertiles composed from a combination of the BMI and WHR, except for HDL-ch and HDL-ch/T-ch, where levels fell. Although the means of these metabolic parameters in each type of obesity were all within the normal range, significant differences were observed between the group with Type-III obesity and the nonobese group for these parameters.<BR>In conclusion, the most“dangerous”subgroup of obesity appeared to be Type-III obesity in which high levels of BMI and WHR coexist.
ABSTRACT
In the present study, we investigated the associations of the body mass index (BMI ; kg/m<SUP>2</SUP>) and the waist to hip circumference ratio (WHR) with metabolic features in 134 Japanese women ranging in age from 24 to 79 years. We found that the BMI was reasonably well correlated with the WHR (r=0.693, p<0.001), which may be related to the health risk profile. The BMI and WHR both showed significant negative correlation with high-density lipoprotein cholesterol (HDL) level, and positive correlation with triglyceride (TG) and plasma glucose (GL) levels and systolic blood pressure (SBP) and diastolic blood pressure (DBP) . Following adjustment for the effect of the BMI, the partial correlation coefficients of WHR with HDL, TG, and GL were lower than those obtained before adjustment, and were not significant. However, the partial correlation coefficient of WHR with HDL/total cholesterol ratio (HDL/TC), SBP, and DBP were significant. These results suggest that the levels of HDL, TG and GL are associated with the BMI among subjects with similar WHR. We therefore propose that a combination of the BMI and WHR would be a superior indicator in obesity screening than the BMI alone.
ABSTRACT
A study was conducted to investigate the validity of bioelectrical impedance measurement (BIM) for determining changes in body composition during treatment of obesity with an exercise and diet regimen. Eleven obese women, aged 38-57 yr (44±6.0 yr), participated in a weight reduction study. Before and after the weight reduction period, body composition was measured by the deuterium oxide (D<SUB>2</SUB>O) dilution and BIM methods. For both methods, the correlation coefficients were of the same order of magnitude under both pre- and postregimen conditions. Mean weight reduction was 3.59±1.518 kg and loss of total body fat was estimated to be 4.8±1.72 kg by the D<SUB>2</SUB>O method and 2.5±1.14 kg by the BIM method. Thus the BIM method underestimated the change in body fat compared with the D<SUB>2</SUB>O method. Changes in resistance (R) and height squared divided by R were not significant at the p>0, 05 level. However, the mean change in fat-free mass (FFM) found by the D<SUB>2</SUB>O method was significantly greater than that found by the BIM method. Furthermore, there was no significant correlation between the changes in FFM estimated by the D<SUB>2</SUB>O and BIM methods. These results show that after weight reduction the BIM method overestimates body composition. It is concluded that the BIM method is not a valid approach for measuring the small changes in body composition that occur during treatment of obesity.