This study was conducted to clarify the validity and availability of inclination of exponential curve-fitting model for oxygen uptake (VO₂) and heart rate (HR) during incremental exercise (I-ECOH) as an index of cardio-pulmonary functional reserve in patients with ischemic heart disease (IHD). A treadmill exercise test was used to measure the VO₂(L/kg/min) and HR (beat/min) during incremental exercise of all subjects. I-ECOH was derived from the following equation : HR=A·exp^B·VO2. The constant "B" represents I-ECOH. The following two identifications were made : 1) the relation between peak oxygen uptake (VO₂peak) and I-ECOH in IHD patients with normal left ventricular function and with chronic heart failure (CHF); 2) the relation between I-ECOH and the New York Heart Association (NYHA) functional classification of IHD patients with CHF.
There were significant differences among IHD patients with normal left ventricular function, CHF patients, normal controls and long distance runners in I-ECOH and VO2peak, respectively (p<0.001). There were inverse correlations between I-ECOH and VO2peak in IHD patients with normal left ventricular function (r=-0.64, p<0.001) and CHF (r=-0.63, p<0.001). I-ECOH could be used to discriminate effectively between NYHA functional classes (p<0.001).
In conclusion, these results suggest that I-ECOH is adequate and useful as an index of cardio-pulmonary functional reserve in patients with ischemic heart disease.

View full abstract

The purpose of this study was to investigate the accuracy of estimating human body composition changes using bioelectrical impedance (BI) methods during a weight-loss intervention. Subjects were forty-three obese men (age : 49.2±10.5 yr, BMI : 27.8±1.7 kg/m²) who completed a 14-week weight-loss intervention. In all subjects, fat mass (FM) and fat-free mass (FFM) were assessed by dual energy x-ray absorptiometry (DXA) as well as single- and multi-frequency BI methods (SBIM, MBIM) before and after the intervention. Resistance parameters were measured by SBIM and MBIM (SBIM : R₅₀ ; MBIM : R∞, R0, and Rfc). In nine subjects these variables were also measured at weeks 1 and 4. Weight decreased (P<0.05) by -8.0±3.2 kg during the intervention while FFM changes averaged -0.4±1.6 kg (DXA), -2.0±1.5 kg (SBIM), and -1.6±1.7 kg (MBIM). BI methods overestimated FFM before the intervention (before ; DXA : 54.4±4.8 kg, SBIM : 56.5±4.3 kg, MBIM : 55.9±4.5 kg). In nine subjects, FFM measured by SBIM (FFM_SBIM) and MBIM (FFM_MBIM) was similar to FFM measured by DXA(FFM_DXA)(after ; DXA : 54.6±5.4 kg, SBIM : 54.6±3.8 kg, MBIM : 54.6±4.1 kg), although BI methods overestimated the FFM before the intervention (before ; DXA : 54.9±5.1 kg, SBIM : 56.9±3.8 kg, MBIM : 56.3±4.4 kg). The ΔFM_SBIM and ΔFM_MBIM were highly correlated with the ΔFM_DXA(SBIM : r=0.87, MBIM : r=0.88). The ΔFFM_SBIM andΔFFM_MBIM were significantly correlated with the ΔFFM_DXA(SBIM : r=0.54, MBIM : r=0.49). The ΔR₅₀ and ΔRfc were also significantly correlated with the ΔFFM_DXA(R₅₀ : r=-0.63, Rfc : r=-0.48). These results suggest that during a weight-loss intervention, 1) BI methods and DXA provide similar estimates of human body composition change, although they overestimate FFM in obese men, and 2) changes of resistance parameters observed with BI methods may estimate human body composition change more accurately.

View full abstract

To investigate the relationship between adolescent sport activity and abnormalities of the lumbar spine on radiography and magnetic resonance imaging (MRI), 237 collegiate athletes (mean age 19.4), representing judo, wrestling, and track, were analyzed from the point of contact or noncontact sports. Radiologic and/or MRI abnormalities of the lumbar spine were found in 68.7% of contact sports athletes (judo and wrestling, n=147), 53.3% of noncontact sports athletes (track, n=90), 69.9% of athletes who have played contact sports over 9 years (C9 athletes, n=83), and 47.1% of atheletes who have done noncontact sports over 9 years (N9 athletes, n=17). Discopathy related abnormalities on radiologic examination were found in 25.3% and 11.8% of C9 and N9 athletes. Disc degeneration on MRI was found in 45.8% and 29.4% of C9 and N9 athletes. Spondylolysis was found in 31.3% of C9, 5.9% of N9, 31.3% of elementary-C (athletes who played contact sports during elementary school, n=96), 32.8% of elementary-L/I (limited contact/impact sports, n=58), and 8.6% of elementary-N athletes (noncontact sports, n=35), respectively. From these results, we concluded that contact sports activity during adolescence induces lumbar spine abnormalities at a higher rate compared to noncontact sports and that spondylolysis is related to contact or limited contact/impact sport activity during elementary school.

View full abstract

This study reviewed the influence of hypoxic training on hypoxic pulmonary vasoconstriction (HPV) sensitivity in the isolated perfused lungs preparation of rats. In addition, the study examined the kind of mechanism involved. Therefore, we inhibited nitric oxide (NO) release of endothelial cells, using on NO synthase inhibitor, and reviewed the impact on HPV.
As a result, the following became clear. 1)Hypoxic training inhibited HPV. 2) HPV was increased by the administration of NO synthase inhibitor L-NMMA, in particular, conspicuously inhibited HPV in the hypoxic training group was increased. 3) The negative correlation between the onset of blood lactate accumulation and HPV was significant.
From the above, it can be concluded that hypoxic training inhibited HPV and NO release for a pulmonary vascular endothelial cell. In addition, we understood that HPV was decreased by hypoxic training as the ability for endurance exercise was increased.

View full abstract

Masked obesity is the presence of obesity based on percent body fat (%BF) when the body mass index (BMI) shows an absence of obesity. To examine the relationship between masked obesity and arteriosclerosis risk factors, we compared both serum lipid levels and the prevalence of hyperlipidemia in male and female high school freshmen with and without masked obesity. Subjects consisted of 403 male and 326 female high school students aged 15∼16 years. Of these, 34(8.4%) males and 36(11.0%) females had masked obesity, defined as 17≤BMI<23.60 and %BF≥25% in males, and 17≤BMI<24.17 and %BF≥30% in females, while the remaining 300 males and 246 females were not obese, having 17≤BMI<23.60 and %BF<25% and 17≤BMI<24.17 and %BF<30%, respectively. For both sexes, serum total-cholesterol (TC), low-density lipoprotein cholesterol (LDLC), triglycerides and the arteriosclerotic index (AI) were significantly higher (p<0.05∼0.01) in those with masked obesity. And many of the subjects with masked obesity had abnormal levels of TC, LDLC and AI, compared with those who were not obese (p<0.05∼0.01). Additionally, we compared both serum lipid levels and the prevalence of hyperlipidemia between subjects with masked obesity and control groups with the same BMI values. As a result, subjects with masked obesity had high serum lipid levels and a prevalence of hyperlipidemia. These results support the existence of masked obesity and suggest that masked obesity is associated with increased serum lipid levels, and thus could be a risk factor for arteriosclerosis in male and female high school freshmen.

View full abstract

Forearm bone mineral content for adult white elite synchronized swimmers is lower than that of normative data (Roby et al. 1988). However, bone mineral density (BMD) in local body regions and the body as a whole are unclear in adolescent synchronized swimmers. The purpose of this study was to examine BMD of adolescent synchronized swimmers. This study also examined the relationship between BMD for young athletes and biological (e. g. morphological and functional aspects) and habitual (e. g. physical activity and nutritional state in daily living) variables. Subjects were nine females selected nationwide out of a large number of synchronized swimmers of fourth to sixth grade in elementary school, who participated in an audition with the committee of synchronized swimming in the Japan Swimming Federation. Chronological and bone age were 13.4±1.0 years and 12.7±0.9 years (n=8), respectively. BMD was evaluated in local regions and the body as a whole by dual X-ray absorbtiometry (DXA). Walking was measured by pedometer, and physical activity and nutritional status were analyzed by activity diary and food weighing method, respectively. As a result, mean BMD in athletes tended to be lower than in normal Japanese girls for lower limbs and lumbar vertebra (L2-L4), while it was almost the same between the two groups for whole body, upper limbs, thoracic vertebrae and pelvis. The correlations between BMD for whole body and bone age, the number of years since menarche, body mass, lean body mass and physical activity in leisure time of daily life were significant. An analysis using a general linear model indicated that bone age and active leisure activity together explained 94.6% of the variance of the BMD. These findings indicate that BMD of adolescent synchronized swimmers tended to be unique in local regions. Furthermore, BMD in athletes was affected by the biological maturation level and physical activity in leisure time of daily life.

View full abstract