Douglas Bag Method Research Articles

Development of the simplified method for estimating lactate threshold

The true response according to the concept of anaerobic during a progressive incrementalload exercise, corresponds to the onset of blood lactate accumulation from a resting level, and it is called lactate threshold (LT). The measurement and analysis of blood lactate, however, is complicated and not popular, so LT is often estimated by 2 criteria of gas exchange parameters (GEPs) described below visually, 1) non-1inear increase in VE and 2) increase in VE/VO_2 Without corresponding increase in VE/VCO2, and it is called ventilatory threshold (VT). The visual inspection to detect VT contains the subjective variation of intra and inter-detectors, so its reliability and reproducibility are poor. The purpose of this study are 1) to examine if the LT is consistent with VT determinated by the modeling of each criterion to avoid the subjective variations, or not, and 2) if either of VT by modeling is consistent with LT well, to develop the new method (algorithm) that executes the estimation of its consisted VT by on-line and real-time processing of GEPs. 21 young male subjects performed an incremental-load ergometer exercise in which the initial work rate was the 4 min unloaded cycling and thereafter its rate was increased 150 kgm every 2 min until exhaustion. GEPS were measured by Douglas bag method continuously, and blood samples for lactate analysis were obtained last 30 sec of each work rate frofn a warmed ear lobe. To detect LT and VT from criterion l, we employed the segmented regression analysis to the data below 85% of VO_2max of LA and VE vs. VO_2, and these were called LT and VT(85%). To detect VT from crit-erion 2, we employed the multiple regression analysis to all data of VE/VO_2 vs. VO_2, and selected the model's order according to AIC. The lowest value of the fitting model was determinated as VT detected by criterion 2, and it is called VE/ VO_2>(lowest). ' As a result, VT(85%) was not always consistent with LT, but VE/VO_2(lowest) was consistent with LT well, so VE/VO_2(10west) was a good predictor to estimate LT by GEPS objectively. The consistence of LT and VE/VO_2(lowest) shows the cause-effect relationship between LT (cause) and VT (effect). It is not safe to perform the exercise test until exhaustion, in particular, for older subjects. So, it is necessary to develop the algorithm that executes the on-line and real-time processing of VE/VO2 data successively during a test. This algorithm can be stopped a test at the time of LT estimation. To consider the on-Iine and real-time processing, we use the point at whlch the slope between 2 adjacent VE/VO2 Changes from minus to plus, that equals VE/VO_2(lowest) substantially, and it is called VE/VO_2(minimum). To be concrete, this algorithm consists of three parts : moving average processing of VE/VO_2(raw data), calculation of the slope between 2 adjacent moving averages, and decision of VE/VO_2(minimum) using the change in slope.

Re-examination of the relationship between lactate threshold and ventilatory threshold

The ventilatory threshold (VT ; determined by gas exchange parameters) has been applied for many purposes regarding to physical working capacity in many studies. VT, however, contains the subjective variation, because it is determined from some criteria of gas exchange parameters visually. Recently, there are some reports that lactate threshold (LT)and VT do not always occur simultaneously. In this study, we employed the segmented regression analysis to estimate LT and VT objectively, and re-examine the relationships of LT computed, VT computed, and VT deterTnined visually. Thirteen young male subjects performed an incremental-load ergometer work in which the initial work rate was the 4 min unloaded cycling and thereafter the work rate was increased 150 kgm every 2 min until exhaustion. Gas exchange parameters were measured by Douglas bag method continuously, and blood samples for LA analysis were obtained last 30 sec each work rate from warmed ear lobe. It is supposed that LA and VE changes against Vo2 during progressive work is fitted by three segment model, so we employed the segmented regression analysis to all data and data below 85% Vo2max of LA and VE vs. Vo2, and estimated LT(all), LT(85%), VT(all), and VT(85%), respectively. VT(visual) was a mean value of four observers who visually inspected the graph of VE, VE/Vo2, and VE/Vco2 vs. Vo2 according to two criteria described below, 1) non-linear increase in VE, 2) increase in VE/Vo2 Without corresponding increase in VE/Vco2. The results of this study were 1) LT(85%) is always consistent with LT(all) and have a standard deviation of about 0.1L/min-Vo2, 2) all variables that computed or inspected by gas exchange informations and LT(85%) do not always occur and these results suggest limitations and invalidity of using gas exchange parameters to estimate LT.

Effect of dietary modifications on lactate threshold and onset of blood lactate accumulation during incremental exercise.

To assess the effect of dietary change on (1) the point at which arterial blood lactate concentration (HLa) increases above the resting value (lactate threshold) and (2) the fixed point corresponding to 4 mM of HLa (onset of blood lactate accumulation; OBLA), five healthy male subjects were put on a mixed diet for 3 days, followed by 4 days of a low carbohydrate diet (a low CHO diet), and then 3 days of a high carbohydrate diet (a high CHO diet). Following each type of diet, the subjects performed a progressive bicycle exercise test, during which concentrations of HLa, pyruvate, FFA, and glucose were analyzed from serial samples of arterial blood, and VO2 was obtained by the Douglas bag method. The results of this study are as follows: FFA was significantly lower, while pyruvate was significantly higher at rest after a high CHO diet than after a low CHO diet (P less than 0.05). These differences continued throughout the incremental exercise, which indicates the incremental contribution of CHO to metabolism after a high CHO diet and vice versa. There was no significant difference in lactate threshold expressed in VO2 among the three conditions. VO2 obtained at OBLA was significantly lower after a high CHO diet than after a low CHO diet (P less than 0.01). It was concluded that the dietary modifications used in this study had no influence on lactate threshold but did affect the point of OBLA. Therefore, dietary conditions should be considered when OBLA is determined using a fixed 4-mM HLa method.

A portable lightweight Douglas bag instrument for use during various types of exercise.

A construction outline of lightweight portable equipment for VO2 measurements by the Douglas bag method is given. The equipment consists of three separate units: an inspiration-expiration valve, a switch directing the expiratory flow, and a disconnectable bag with stopcock. The ease of operation assures good reproducibility of the results. Experiences during maximal speed skating are described. Use of the equipment demands only simple operations by the subject, which do not interfere with the exercise.

A new development of mass spectrometer and computer system for the respiration and circulation studies

A new mass spectrometer computer system have been developed for the application of lung and circulatory function test and physical fittness. The measuring variables are V E, VO 2, VCO 2, H.R. and their derivatives. These factors are displayed in digital form and the drawing on the X-Y plotter. The accuracy of the measurement is comparable with that of douglas bag method in the steady state of the respiration. In the breath by breath mode, some correction should be performed for the exact alveolar gas exchange due to the lung strage.

The effect of stride length variation on oxygen uptake during distance running.

Ten recreational runners (mean VO2max 64.7 ml . kg-1 . min-1) underwent a 5-d acclimation period to treadmill running at a 7 min . mile-1 pace (3.83 m . s-1) for 30 min each day. During these runs their freely chosen stride lengths were determined and expressed as a percentage of leg length (%LL). On two subsequent testing days stride length was systematically varied over a range of +/- 20% LL about the freely chosen value. O2 uptake was determined by the Douglas Bag method. All subjects exhibited a stride length of which O2 uptake was minimized, although the individual profiles varied considerably. The mean increases in VO2 were 2.6 and 3.4 ml . kg-1 . min-1 at the short- and long-stride length extremes, respectively. During unrestricted running deviations from optimal stride length caused a mean increase in VO2 of 0.2 ml . kg-1 . min-1. The relatively efficient running patterns used by the subjects during unrestricted running indicate either an adaption to the chosen stride length through training or a successful process of energy optimization.

Measurement of metabolic rate in hyperoxia

The conventional Douglas bag calculation for estimating O2 uptake (VO2) during exercise in normoxia and hyperoxia, VO2 = VE . (FIO2 . FEN2/FIN2 - FEO2), was tested against two other valid calculations: the Fick equation, VO2 = VI . FIO2 - VE . FEO2, and the equation VO2 = VI - VE - VCO2 (VE and VI are expired and inspired ventilation, respectively; FEO2 and FIO2 are expired and inspired O2 contents, respectively; FEN2 and FIN2 are expired and inspired N2 contents, respectively; and VCO2 is CO2 production.). These calculations are based on different assumptions, in part, and are affected to a varying degree of errors in volume or gas fraction measurements. With the conventional Douglas bag technique, we found evidence of an overestimate of VO2 during hyperoxia. After the introduction of a mixing chamber for sampling expired air, the means of the three methods were not significantly different. The variability among the methods was least with the conventional calculation but increased with higher O2 fractions. The average VO2 for submaximal exercise in hyperoxia was not significantly different from that of normoxia. VO2 max was significantly higher in hyperoxia. The increased variability of the Douglas bag method in hyperoxia may lead to overestimates of VO2 max unless special precautions are taken.

Oxygen consumption and hemodynamic response of exercises used in training of patients with recent myocardial infarction.

We investigated oxygen consumption (ml/kg/min) and hemodynamic response (peak heart rate-systolic blood pressure product) to individual exercise activities before and after exercise training in 22 male postmyocardial infarction patients (PMIP). Activities included swimming, walk/jogging, volleyball, calisthenics and exercise dance routines. Oxygen consumption was determined immediately after exercise by the Douglas bag gas collection procedure and, in selected patients, by a Max Planck respirometer during exercise. Hemodynamic data were obtained by pulse count and cuff sphygmomanometer. The increase in oxygen consumption and the decrease in rate-pressure product after each activity were significant (p less than or equal to 0.01). There were no differences in oxygen consumption between the Max Planck respirometer technique and collection (Douglas bag method) immediately after exercise. The oxygen consumption obtained for PMIP compared with available cumulative data on normal subjects is significantly variable, suggesting the need for caution when prescribing exercise for the PMIP based on energy costs of standard exercise measurements in normals. This was particularly relevant because of the significantly high oxygen consumption incurred during swimming.

A respirometer for use in the field for the measurement of oxygen consumption. 'The Miser', a miniature, indicating and sampling electronic respirometer.

Abstract A respirometer system for the measurement of oxygen consumption in the field is described. The design is based on well-tried principles. The system consists of three parts: a photoelectric version of the Wright gasmeter, a control unit incorporating volume counter, timer and display, and a vacuum sampler. The instrument is compact, weighing about 600 g, and robust. It is powered by rechargeable cells and has an endurance of about 8 h of continuous running. The sampler consists of an evacuated aluminium container and flow regulator carried on the control unit. Sub-samples of any desired volume are taken at isovolumetric intervals, ensuring that the whole sample is representative of the total expired air. The operating of the instrument is simple, sampling rate and sub-sample volume are set on the basis of expected minute ventilation and the desired duration of the measurement. There was little difference between [Vdot] o 2 measured with the MISER and that using the conventional Douglas bag method....

Aerobic requirements and maximum aerobic power in treadmill and track running

Treadmill and track running comparisons were made on eight track athletes. Oxygen uptake (VO2) during steady-state and maximum aerobic power (VO2 max) were measured in a discrete series of three speeds, and at maximal effort. Running speeds were always in sequence from slowest to fastest. Expired air was collected from the runner by the Douglas-bag method, and analyzed by the Lloyd-Haldane technique. Neither VO2 max nor aerobic requirements of running were significantly different in track and treadmill determinations. There were several correlations: 1) VO2 max with body weight (r = .83 P less than .02), 2) treadmill and track determinations of VO2 max (r = .95, P less than .01) and 3) VO2 ml/kg with running velocity m/min (r = .91, P less than .01) where the regression was linear and may be represented by the equation Y = 5.36 + 0.172X, where Syx = 2.7 m102/kg. It is concluded that treadmill determinations of oxygen uptake may be validly applied to track running in calm air within the range of 180...260 m/min.

A new technique for the long-term stable measurement of energy expenditure

Summary A new, open-circuit, flow-through technique for frequently repeated measurements of energy expenditure is described. It is designed mainly for subjects lying in bed and can be applied to severely injured patients, i.e. patients with extensive burns. The measurement will not cause any discomfort to the subject, who does not have to co-operate. The energy expenditure was assessed at ±2.6 per cent when pulse technique was used with ambient air as the calibration gas. No systematic error (95 per cent tolerance limits) compared with the conventional Douglas-bag method was found. The technique described is flexible, because all calculations are performed in a connected computer.

Apparent Efficiency and Storage of Elastic Energy in Human Muscles during Exercise

Abstract3 subjects ran on the treadmill (10 km/h) against varying horizontal impeding forces. One subject was further studied during the same kind of walking and bicycling on the treadmill, and during work consisting in lowering and lifting the body by flexing and extending the legs from a standing or sitting position at varying frequencies, with or without rebound in the deepest position. Workpower (W kcal/min), and the corresponding steady state metabolic rate (E kcal/min, Douglas bag method) were measured. Apparent efficiency (N) was calculated as Δẁ/ΔÈ× 100 %. During load running N was 53.8, 37.6 and 41.2 %, respectively, in the 3 subjects. In the subject more extensively studied N was: running 53.8, walking 32.3, bicycling 25.1, knee‐flexions (deep or half) with rebound 39.4 or 41.0, without rebound 26.1 or 21.9 %. These variations in N % were explained in accordance with the possibilities for re‐using the energy, absorbed and stored in the muscles as elastic energy during a phase of negative exercise, in a subsequent phase of positive exercise. The condition of this is that the positive phase follows immediately after the negative. A calculation showed that during running 35–53 % of the energy absorbed during the negative phase was re‐used. Corresponding figures for walking and rebounding knee‐extensions were 23 % and 34 %, respectively, while in bicycling and knee‐extensions without rebound all of the negative work degenerated into heat.

種々な吸気酸素分圧における全身持久性

The cardio-respiratory function was observed during treadmill exercise inhaling different partial pressure of oxygen. The inspired air contained 14% O_2 (Po_2 102 mmHg), 21% O_2 (Po_2 159 mmHg), and 60% O_2 (Po_2 448 mmHg). The air in the decompression chamber was Po_2 100 mmHg which was equivalent to about 3,700m altitude. The endurance running time to exhaustion on the treadmill, maximum oxygen intake, maximum cardiac output, and maximum pulmonary ventilation were measured on 9 male subjects from 23 to 29 years of age. They were submitted to the maximal exercise by a motor driven treadmill inhaling the four different contents of O_2 levels mentioned above. The oxygen intake was measured by Douglas bag method. The CO_2 rebreathing technique described by K. Klausen was used for determining cardiac output. The heart rate and the respiratory frequency during exercise were continuously recorded. The gas samples were analyzed by micro-Scholander's apparatus, The running time to exhaustion on a treadmill in nine subjects were 3 minutes 28 seconds, 5 minutes 43 seconds, 7 minutes 37 seconds, and 3 minutes 37 seconds in the average, when the subject inhaled the oxygen of 14%, 21%, 60%, and the air in the decompression chamber respectively. There was found a close relation between physical endurance time and maximum oxygen intake, whereas the maximal cardiac output was kept unchanged despite of changing inspired oxygen contents. No consistent changes in the lung diffusing capacity were observed from ordinary air to low O_2 inhalation during maximal exercise. The results suggested that decreased maximum oxygen intake at low O_2 inhalation was due to incomplete oxygenation of arterial blood due to the reduced Po_2 in the inspired air.

The Effects of Breathing 100 Percent Oxygen during Rest, Heavy Work, and Recovery

Abstract The effects of breathing 100% oxygen on resting, exercise, and recovery oxygen consumptions, pulmonary ventilation volumes, and heart rates were observed on six highly conditioned male athletes. The subjects rode a bicycle ergometer at a heavy work load for five minutes, breathing either normal air or medical oxygen. Ventilation volumes were determined by the open-circuit Douglas bag method, measuring inspired and expired volumes. Gas samples were analyzed for nitrogen and oxygen concentrations on Van Slyke and Beckman gas analyzers, and heart rates were recorded via a telemetry-electrocardiograph system. The results indicated a substantial increase in resting oxygen consumption, a decrease in resting ventilation volume, a marked decline in exercise and recovery ventilation volumes, and an insignificant lowering of the energy cost of exercise during the oxygen experiments. No appreciable differences were noted in heart rates between the oxygen and air experiments.

Comparison of CO2 rebreathing and acetylene methods for cardiac output.

The cardiac output during rest and work was determined by a CO2 rebreathing method as suggested by Defares. The partial pressure of CO2 in the mixed venous blood (PvCOCO2) was calculated from the rise of the CO2 percent in a Grollman bag during rebreathing. In the rest experiments the partial pressure of CO2 in arterial blood (PaCOCO2) was obtained from analysis of alveolar samples taken by the Haldane-Priestley direct sampling method. In the work experiments the PaCOCO2 was calculated using the Bohr formula and a dead space estimated from Asmussen and Nielsen's data. The metabolic rate including both O2 uptake and CO2 output was determined by the Douglas bag method. In each experiment the acetylene method as described by Christensen was applied after the CO2 rebreathing method. The values obtained by the two methods were almost identical, the standard deviation for all experiments being ±7.3%, and were of the same magnitude as those obtained by others with the dye-dilution or direct Fick method both during rest and work. cardiac output at rest and work; arterial Pco2 and venous Pco2 at rest and work; stroke volume at rest and work Submitted on November 25, 1964

Comparison of Speed and Energy Expenditure for Two Swimming Turns

Abstract Speed and energy expenditure of the closed and open freestyle swimming turns were determined on six male swimmers. The subjects were tested while in a post-absorptive state. Resting metabolic rates were determined utilizing an open-circuit, Douglas bag method. The test included swimming a distance of 70 ft. and performing either the closed or open turn without taking a breath. Upon completion of the test, the subject breathed into a Douglas bag for 15 min. Each turn was timed with a stopwatch; a turn started 3 ft. 10 in. before touching and ended as the feet left the side of the pool. Statistical treatment of the date revealed no significant difference in energy expenditure. However, the closed turn proved to be significantly faster than the open.

Studies on the Body Composition and Nutritional Status

The correlation analyses of the body composition were studied on 14 men who were members of our institute as the first experiment for the purpose of evaluation of human nutritional status. The mean age of these men was 21.9 years old. All measurements were conducted at fasting condition in the forenoon.Methods: The basal metabolism was measured by Douglas-bag method. The skinfolds were measured with the Minnesota caliper model at the pressure of 10g/mm2 of the skin surface, and at five sites of the chest, upper arm, upper ileocrista, subscapula and upper knee. The body density was computed from the volume of displaced water by submersed body at the maximal expiration, the body weight in air and the residual lung volume. The volume of displaced water was determined by reading the side burette which was attached to the tank. The error of this method was estimated about ±100ml. The residual air was determined by the forced breathing method of Lundsgaard and Van Slyke. The nitrogen contents of the oxygen gas, expired gas and alveolar air were analysed with the Showlander's apparatus. The body water measurements were made by the antipyrine space method of Brodie and Soberman et al. The serum cholesterol was determined by the modification of Bloor's method.Results: The mean skinfold thickness of six sites was 5.8mm (table 1). This value was only about a half of that in the reports for American (Brozek, Neeman, Pascale).The body density was in the range of 1.0542 to 1.0903 and showed a mean value of 1.0725. The body water (antipyrine space) was in the range of 47 to 65% of body weight and was 57.6% as a mean value.The body fat estimated from the antipyrine space showed the variable values of 19.0, 19.7 and 21.3% of body weight respectively according to each author's equation, and the fat values calculated from the body density by the equations of Keys and Brozek and Pace and Rathhun were 9.0 and 13.0%, as shown in table 2. Such as this, the coincidence was not recognized between the body fat values calculated from the antipyrine space and from the body density.In the correlations between body density and various skinfold thicknesses, the coefficient value was the highest on the chest and were higher on the upper arm and subscapula as shown in table 3. The correlation between body density and the sum of skinfold thicknesses of six sites showed the fairly high value of γ=-0.71.The correlations of the basal metabolism (cal/hr.) to the body weight (kg.), body surface area (m2) and fat-free body mass (kg.) were γ=0.626, γ=0.872, γ=0.874 respectively as shown in table 3. These coefficient values showed that the correlation of the basal metabolism to the fat-free mass was as high as to the body surface. In the correlations of basal metabolism (cal/hr. kg.) to the body density and to the skinfold thickness (the sum of six sites) fairly high coefficients of γ=0.780 and γ=-0.819 were seen.The correlation between the serum cholesterol and the skinfold thickness was not recognized in these healthy subjects.

Studies of the Basal Metabolism of Japanese (Report 10)

Whether there is a regular fluctuation of female basal metabolism related to menstrual cycle has not been decided yet, in spite of many authors' efforts. Some of them recognized the fluctuations of the basal metabolism, but did not found a common rule among them.However, concerning the body temperature, a physiological rise right after ovulation continued until next menses has been confermed in most of healthy women. So, this experiment was conducted, expecting that it may be a easier way to survey the basal metabolism correlated with body temperature, in order to find out the common rule of its fluctuation.Daily basal metabolism of two girls aged 21 and 23 years measured by Douglas bag method for 38 days. Body temperature under tongue was surveyed with a mercury thermometer equipped in special accuracy.Results were as follows:(1) The correlation coefficients between basal metabolism and body temperature wer amounted to 0.5-0.7. The basal metabolism is usually influenced by many kinds of factors, therefor these correlation would mean “basal metabolism is in a parallel relation with body temperature”.(2) The maximum deviations from arithmetic mean of the basal metabolism during 38 days were ±7% and ±6% in two girls. The same kind of deviations of 3 girls conducted by a respiration chamber method in 1936 at this institute were ±%, ±9%, and ±7%. These results show that Douglas bag method can not be inferior in accuracy than chamber method.

Basal metabolism as determined by the respiratory exchange

Recent work upon mental disorders has shown that there are important changes in the endocrine organs as well as in the central and sympathetic nervous system. Changes have been especially studied in the sex glands and in the thyroid; and it seemed evident that the determination of the basal metabolic rate of mental hospital patients might do much to add to our knowledge of disorders of the working of these glands. The present research was undertaken under the direction of the late Sir Frederick Mott, who was Honorary Director to the Joint Board of Research for Mental Diseases, City and University of Birmingham. From the beginning it was evident that the usual Douglas bag or spirometer methods, involving mouth and nose pieces or a mask, were quite unsuitable for the work in hand, it being absolutely necessary that the disturbing factors of fear, anxiety and excitement should be eliminated. A chamber was, therefore, constructed similar to one which Prof. J. S. Haldane uses for various experimental purposes, in which the patient could sit, lie or sleep without disturbance for a period of two hours, the metabolism being measured by determining the changes in the air of the chamber at the end of this period. As, however, these changes are small, a special modification of the Haldane air analysis apparatus was required.

A preliminary study of the energy expenditure and food requirements of women workers

The large share which women have taken during the war in industrial work has brought out the importance of possessing reliable data on which to base a fair assessment of their share in the available food supply, and has also revealed the paucity of our knowledge with regard to the energy expenditure of women workers under factory conditions. The food requirements of manual workers are obviously to the largest extent dependent on the energy expenditure of the individual. A scientific system of assessing this expenditure, expressed in calories, may be based on two methods. In the first, which may he called the statistical method, we arrive at the result by -indirect means. The actual amounts of the various foodstuffs consumed by a large number of workers are weighed, and from their contents in proteins, fats and carbohydrates, the energy value of the food consumed is calculated. The second method, which may be called the direct method, aims at the direct determination by suitable methods of the energy expenditure of the worker during sleep, recreation, and work. This procedure is a prior preferable to the statistical one, but owing to inherent practical difficulties, it has not so far been applied to industrial workers. It is obvious that the complicated and expensive installations necessary for direct calorimetry are unsuitable for work under factory conditions. It was possible, however, to make use in the workshop of the method of indirect calorimetry, the general application of which has been so greatly extended by the introduction of the Douglas bag method.