Massage and warm compresses to the breast have been commonly used for stimulating and/or increasing blood flow to the breasts, and for enhancing lactation consequently. However, more effective and easier remedies seem to be necessary. The vasodilating and warming effects of ceramics far-infrared radiation were studied. Based on the results obtained, the effect of a ceramic disc on lactation, attached to the breast skin, was evaluated in 27 puerperal women who had had poor lactation previously and in 36 with currently poor lactation monthly until weaning. Approximately 3/4 of these puerperal women enhanced lactation significantly one month after attachment and l/2 of the women were able to breast-feed until weaning. Thus, we found that ceramics far-infrared radiation may be an effective remedy for enhancing lactation.

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For the purpose of determining the most reasonable lying posture for pregnant women, we investigated the lying positions of both 247 non-pregnant women and 302 pregnant women during sleep. As for the rate of each position during the entire period of observation. 33.2% of the non -pregnant women were in the supine position, 41.2% in the lateral position, 18.4% in Sims' position and 7.1% in the prone position. In the pregnant group, the rate of supine position, simple lateral position and Sims' position was 34.2%, 52.2% and 12.7%, respectively, but the rate of the prone position was limited to 0.8%. All of the gravidas assuming the prone position were at less than 16 weeks of gestation. Non-pregnant women could sleep in a variety of positions, but pregnant women could assume the prone position during sleep only in the stage when the abdomen is not yet prominent or distended. Pregnant women were restricted significantly, either consciously or unconsciously, with progress in gestation.

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Peumatic caisson work in Japan has been come into the operation since 1924. Afterward, this technique of compressed air work has been widely utilized in the constructions of foundation basements, shafts of the bottom tunnel shields for subway and so forth. While the using this technique of compressed air work means that workers have to be exposed to hyperbaric environment, this technique has risks of not only decompression sickness (DCS) but also toxicity of poisonous gas and/or oxygen deficiency. However, this technique is independent of city construction work and the operation of compressed air work higher than 5ATA (4.0kg/cm2G) is actually been planning recently. Accordingly unmanned caisson work is considered as a better technique for such higher pressurized work, even though workers must enter into hyperbaric working fields for mainte-nance or repair of unmanned operated machinery and materials. This research is to establish the safe work under hyperbaric air environment at 8ATA.

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Effects of skin resistance on impedance values were studied in order to propose reliable determination of body composition in human. Analysis of the data indicated that impedance values (Z=(R2+Xc2)0.5) varied considerably in the following conditions: l) 2301±97.8 ohms when electrodes were directly attached; 2) 490d:52.5 ohms when electrodes were at tached imme-diately after use of alcohol; 3) 584i44, 1 ohms when electrodes were attached immediately after use of alcohol with electrode gel; and 4) 589i45.0 ohms when electrodes were attached in the order of elimination of skin resistance - use of alcohol - use of electrode gel. We suggest that impedance obtained by the bioelectrical impedance analysis should be measured immediately after elimination of skin resistance at least with electrode gel.

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Althouh physical training does not affect CO₂ chemosensitivity at rest, different kinds of physical training affect hypoxic ventilatory chemosensitivity at rest in different ways. On the other hand, a number of studies indicated that the mechanism of exercise hyperpnea is related to hypoxic chemosensitivity.

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Characteristic patterns of changes in pulmonary diffusing capacity (DL) at rest and during exercise were Investigated and characteristics of normal DL values concerned on sex, age, and ethnic groups were examined by viewing our studies and other reports. The relation of DL and pulmonary capillary blood volume (Vc) was represented as a logarithmic regression at rest and as a linear regression during exercise. The curve relation at rest is considered to show that the Increase in Vc mainly reflects the process of transport from pulmonary capillary recruitment to pulmonary capillary dilation. The increasing rate of DL was not decreased during exercise, which seemed to be due to an increase in pulmonary blood fllow accompanying exercise. The linear regression was also found between DL and oxygen intake during exercise and the slope was always constant among individuals and among subject groups. The general results concerned with sex difference in Japanese or ethnic difference between Japanese and Caucasians in both sexes could show that DL per stature was greater in males or Caucasians than in females or Japanese in young adults, however, the sex or ethnic difference disappeared in middle or old aged group. DL per alveolar volume which showed no sex or ethnic difference in young adults, was greater in middle or old aged group of females or Japanese than in that of males or Caucasians.

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This paper reviewed in short neural and humoral factors which might be responsible for inducing exercise hyperpnea. As one of the neural factors afferent signals which arise in the exercising limbs and are transmitted via group 111 or IV high threshold sensory fibres were involved. The other neural factor is command signals originating in the central nervous system and being fed onto the respiratory center. Hypothalamic locomotor region is assumed to be a possible locus to integrate these peripheral and central neural signals. There are enough evidences to believe that humoral factors medlated via cardiac output is also essential for the hyperpnea. Changes in CO₂ is well correlated with those of the in dynamic as well as in steady-state response. Oscillations in PaCO₂ Can be assumed to play a role to link metabolic CO₂ changes to those in ventilation. Thus, no single factor can explain the whole process of exercise hyperpnea. Poon's optimization model may give a key to integrate complicated and coflicting experimental resuits in a unique concept.

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To investigate cardiovascular adjustments to combined stress of gravity and exercise during dynamic exercise prolonged over 60 mlnutes in upright positlon, the three experiments were carried out. In Experirnent I, as performing moderate upright bicycling (66% VO₂max) until exhaustion (average 86 minutes) in 4 trained men, changing manners of cardiovascular adjustments were shown in three phases, which were (1) regulating set-point body teperature, (2) making to maintain suitable blood pressure, and (3) failing to control the blood pressure. In Experiment II, as performing moderate supine cycling (55% VO_2max) for 50 minutes under several LBNP conditions In 5 sedentary women, there were correspondingly similar changing manners of the cardiovascular adjustments to each of the phases given in Experiment I. In Experiment 111, as examining tolerance of orthostatic circulatory regulation, the tolerance was significantly correlated to VO_2max and lean body mass (LBM) (both p<0.05) in 8 sedentary women. When a moderate upright exercise is performed over 60 minutes in upright position, the performance should be influenced by total muscle mass indicated by LBM as well as by VO_2max, because the muscle mass could play a valuable role in the tolerance of orthostatic circulatory regulation vs. gravity.

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Ventilatory and cardiovascular responses to isometric exercise, with special reference to hand-grip exercise, were reviewed. Blood flow through the forearm (FBF) during muscular contraction is dependent on relative strength to iMVC (maximum voluntary contraction), duration of exercise, and hand temperature. FBF could attain steady state during exercise with intensities less than 15% MVC. Heart rate (HR) starts to increase with a latency as short as 0.4 to 0.6 sec in conscious animals and men in response to voluntary as well as electrically induced isometric exercise. This response is vagally transmitted. The sympathetic nerves mediated HR response with a longer delay is also found. Cardiac contractility is augmented via sympathetic p-receptors during isometric exercise. W'ith aging, HR response tends to be intensified, whereas, stroke volume response tends to be depressed. Thus increased cardiac output is resulted in elevated arterial blood pressure. Total vascular resistance is reported to be unaltered, or to increase, despite of consistent increase in muscle sympathetic activities during the isometric exercise. Ventilation is augmented during exercise, but the pattern of its response is not in full agreement among investigators. The underlying mechanisms to elicit those responses are discussed.

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In order to study respiratory transients during exercise, we examined breath-by-breath gas exchange kinetics during constant-load work. Five male subjects performed cycle ergometer tests which 6 min of constant-load work (150, 200, 250W) followed 50W base line work. and Vo, measured at the mouth ((Vco₂)_E ((Vo2₎_E) and estimated at the alveolar level ((Vco₂)_A, (Vo₂)_A) were computed breath-by-breath. The kinetic parameter (time constant) of first- and second·order exponential model was estimated using nonnear least-squares method. Our results demonstrated that a relative stability of P_ETO2, P_ETCO2, and R at their control values in the first phase. Independent of work intensities, breath-by-breath variation in gas exchange measured at the mouth was larger than those in gas exchange estimated at the alveolar level both at a non-steady state and a steady state. The time constants of (Vo₂)_A and (V_o2)_E were varied with increase of work load intensity.

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In the present study, the system of oxygen uptake (VO₂) during ramp function exercise protocol can be studied to provide infonnation about the physiological mechanisms underlying the process. The values of maximal oxygen uptake (VO_2max.) and gas exchange threshold (GET) were reproducibly obtained using ramp test protocol. On the other hand, the determination of VO₂/work rate should be restrict to below the exercise intensity of the GET. Therefore, ramp exercise test might be usage for determination of VO_2max, GET and/or VO₂/work rate (i.e., work efficiency). The data obtained in this study concerning the mean response time (MRT) suggests that the ramp test is not a linear, first-order system. Therefore, the ramp exercise test Protocol is recommended for the determination of VO₂ GET and work efficiency, but not for MRT.

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Present study was undertaken to elucidate possible distortion of phase response and amplitude response of various respiratory parameter such as VO₂, VCO₂ and V_E to sinusoidal work load by comparing model analysis with manual analysis. Also, an attempt was made to determine whether there is any relationship between the characteristics of response of these parameters and the aerobic capacity of subjects, bix healty male subjects were performed exercise on an electrically braked bicycle ergometer for 32 min. The work load was varied siunsoidally between 30 watts and 60% V0_2max being under anerobic threshold with periods from 1 to 16 min. These paramerers were determined in breath-by-breath mode with a computer system and mass spectrometer. In model analysis, amplitude and phase responses were well discribed by first order exponential model, and strong correlations were observed between magnitude of phase response or time constant of amplitude response and aerobic capacity. Manual analysis revealed that respiratoiry responses to sinusoidal work load are not completely sinusoidal but somewhat distorted forming saw-tooth waves with steeper downslopes.

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The purpose of this study was to investigate the limitation for applying a linear model to the cardiorespiratory control system. Four subjects performed the two types of exercise bouts, constant (CONST) and pseudorandom (PRBS) exercise, on an electrically braked cycle ergometer at three different work rates. The target work rate of CONST were set to 80. 100, 120 % of the individual anaerobic threshold (AT). In PRBS, the work rates were varied between i 10% of the individual AT around the respective target work rates of CONST. Although the spectral density of beat-to-beat heart rate fluctuations showed the conventional patterns for most cases, there was no obvious difference between CONST and PRBS. These results indicated that the variation of ±10% of AT did not affect the heart rate variation as the output response, suggesting a dilemma inevitable to apply a linear model based on the transfer function.

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Many interrelated physiological and/or morphological factors have been demonstrated to influence endurance exercise performance. Some of these factors include skeletal musculature, running economy, maximal oxygen uptake (VO_2max), maximal steady state (MSS), onset of blood lactate acumulation (OBLA), onset of plasma lactate accumulation (OPLA), and anaer-obic (or lactate) threshold (AT or LT). The present paper focuses mainly on VO₂max, MSS, OBLA, OPLA and LT, all of which have been postulated as a prerequisite in endurance exercise success. This paper consists of : (1) significance of La-related variables, (2) Iongitudi-nal studies, (3) comments, and (4) conclusion. Briefly, it is suggested that estimation of endurance exercise potential could be obtained with relatively high precision using laboratoriously measured La-related variables. The most critical determinant of endurance exercise performance such as marathon time is considered running velocity (V) at which LT is detected (vLT), VO₂@LT, or V@MSS, while V@OBLA appears to be the best predictor of performance in endurance events of 16 km or shorter distances.

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The recent modeling technique to lactate (La) kinetics in exercise, and its availability, application, and limitation were summarized. Two examples were come up for discussion. One is the application of the compartment model (i.e., the description by the linear differential equations) to systemic La kinetics in exercise, and the other is the current controversy on anaerobic threshold, that is, the reexamination of the several proposed models of blood La kinetics during ramp exercise. In conclusion, considering the various limitations in current in vivo experimental approach on man, the theoretical approach with mathematical modeling, as one of the major strategies, gives full play to clarify the La metabolism in exercise.

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Metabolic fate of lactate after strenuous exercise which lasted 2∼3 min was investigated in rats and mice. <13>^C-labeled lactate or glucouse was injected into the aorta of rats through an catheter. <14>^C-glucose was injected intraperitoneally into the mice after supramaximal exercise. The mice ran twice with a 4 hr interval to investigate muscle <14>^C-lactate metabolism which was produced from muscle <l4>^C-glycogen. A great deal of blood and muscle <14>^C-lactate was expired as <l4>^CO₂ after the exercise. The results indicate that oxidative removal is the major fate of lactate metabolism after strenuous exercise and that blood glucose is the major substrate for muscle glycogen resynthesis. Light intensity exercise after strenuous exercise (active recovery) enhances oxidative removal of blood and muscle lactate. Gluconeogenesis from lactate to glycogen within the skeletal muscle is not a major pathway of muscle lactate metabolism, while high intensity training can activate this pathway.

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Calf blood flow (CBF), heart rate (HR), whole-body VO₂ were measured in 13 active women (aged 20.8 yrs) while walking or running at various speeds up to near exhaus'tion. CBF during walking increased linearly in relation to speed in the range 60·100 m/min, and thereafter it levelled off. CBF during running showed a small increase up to 180 m/min, then decreased significantly (p<0.01) from 24.51 ml/100ml calf/min to 19.62 ml/100 ml calf/min. VO₂ corresponding to peak CBF (BFpeak-VO₂) averaged 66.39% VO_2max, which was significantly lower (p<0.05) than the anaerobic threshold (AT;74.48% VO_2max) determined using gas exchange parameters. Significant correlation coefficients of 0.695 (p<0.01) and 0.708 (p<0.01) were obtained between BFpeak-%VO₂ and AT-%VO₂, and BFpeak-%VO_2max and AT-%VO_2max. The magnitude of CBF was not correlated significantly with AT or VO₂max. Levelling-off or decrease of CBF at higher speeds, approximately 10% below AT, suggested that an inadequate blood supply will possibly result in mismatching between oxygen delivery and muscle oxygen demand and that this would lead to switching over to anaerobic energy generatlon.

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This article reviews current evidence regarding neuromuscular regulation and metabolism during exercise. Particular emphases are given on the relationship between motor unit (MU) activity, including single MU analysis results and spinal a-motoneuron excitability, and cardio-respiratory response and blood lactate during dynamic exercise. In addition, a close physiological link between muscle energy metabolism and excitation-contraction processes (failure of one will affect the extent of the other) is summarized in the light of recent nuclear magnetic resonance (NMR) studies and results of neuromuscular disorder patients.

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Magnetic resonance imaging (MRI) is superior to ultrasonography and X-CT especially in density resoiution in soft tissue. 31P NMR provides information on metabolism, IA'hich has not been obtained in vivo by conventional methods, such as phosphocreatine (PCr), inorganic phosphate (Pi), ATP, and intracellular pH. We used MRI and <31>^PNMR spectroscopy to study skeletal muscle metabolism of human and rat. These NMR results suggested that l) estimatlon of muscle fiber composition, 2) evaluation of muscle ATP turnover and 3) imaging of local muscle fatigue are possible.

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