Journal of Applied Physiology Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 88: 1175-1180, 2000;
8750-7587/00 $5.00
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (9)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by van der Ploeg, G. E.
Right arrow Articles by Crockett, A. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by van der Ploeg, G. E.
Right arrow Articles by Crockett, A. J.
Vol. 88, Issue 4, 1175-1180, April 2000

Comparison of two hydrodensitometric methods for estimating percent body fat

Grant E. van der Ploeg1, Simon M. Gunn1, Robert T. Withers1, Andrew C. Modra1, and Alan J. Crockett2

1 Exercise Physiology Laboratory, School of Education, The Flinders University of South Australia, Adelaide 5001; and 2 Respiratory Function Unit, Flinders Medical Centre, Bedford Park, South Australia 5042, Australia


    ABSTRACT
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

This study compared the two following hydrodensitometric methods for estimating percent body fat (%BF): 1) estimation of residual volume (RV) by helium dilution before and after measurement of immersed mass at RV, and 2) determination of immersed mass at a comfortable level of expiration (approximately functional residual capacity) with measurement of the associated gas volume by oxygen dilution. Twelve men [27.9 ± 7.5 (SD) yr; 79.32 ± 12.79 kg; 180.5 ± 9.9 cm] were tested for %BF via both methods on each of two separate visits within 3 days by using a counterbalanced design. The two helium dilution measurements yielded a technical error of measurement of 0.2% BF and an intraclass correlation coefficient of 0.999. Corresponding values for the oxygen dilution method were 0.4% BF and 0.999, respectively. There was no difference (P = 0.80) between the helium dilution (16.9 ± 9.3% BF) and oxygen dilution (16.9 ± 9.4% BF) methods, and the individual differences ranged from -0.7 to 0.6% BF. The interclass correlation coefficient between the two methods was 0.999 with a SE of estimate of 0.4% BF. Whereas both methods were precise and reliable and yielded similar results, the oxygen dilution technique was more expedient and was preferred by the subjects because they were not required to exhale to RV.

helium dilution; oxygen dilution; residual volume; body density


    INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

SPORTS SCIENCE RESEARCH and adult fitness programs frequently require an assessment of the percent body fat (%BF). Underwater weighing or hydrodensitometry is the most frequently used laboratory procedure for estimating %BF. This method uses Archimedes' principle to calculate body density (BD) from measurements of mass in air, immersed mass, water temperature, and the volume of gas in the respiratory system [normally the residual volume (RV)] when the immersed mass is measured. If it is assumed that the densities of the fat mass and fat-free mass (FFM) at 36°C are 0.9007 (9) and 1.1000 g/cm3 (3), respectively, then the %BF can be estimated from the Brozek et al. (3) equation
%BF = <FR><NU>497.1</NU><DE>BD</DE></FR> − 451.9
It is generally considered that inaccuracies associated with the determination of the gas volume in the respiratory system are the largest source of error in the measurement of BD and hence the %BF. The RV is frequently measured by either the closed-circuit helium dilution (14, 15) or closed-circuit oxygen dilution method (22, 23). The helium dilution method requires a spirometer and helium analyzer. The advantages of the oxygen dilution method are that these expensive items of equipment are replaced by an inexpensive rebreathing bag, and the gaseous composition of the bag can be measured by carbon dioxide and oxygen analyzers, which are two of the most common items of equipment in an exercise physiology laboratory. Our modification of the oxygen dilution method involves expiration to a comfortable level or approximately functional residual capacity (FRC). This is less stressful for the subject because the immersed mass is not measured at RV. However, hydrodensitometric differences between these closed-circuit helium and oxygen dilution methods have not been examined. Accordingly, the aim of this investigation was to determine whether there are differences between the two following methods of measuring BD: 1) measurement of immersed mass at RV with this volume being determined by the criterion method of helium dilution both before and after the underwater mass trials; and 2) expiration to a comfortable level (approximately FRC) with this somewhat variable volume of gas in the respiratory system being measured by oxygen dilution each time an underwater mass is recorded.


    METHODS
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

Subjects

Twelve men [27.9 ± 7.5 (SD) yr; 79.32 ± 12.79 kg; 180.5 ± 9.9 cm] volunteered for this project, which was approved by the Flinders Medical Center's Committee on Clinical Investigation. Informed consent was obtained in accordance with the established protocol for human subjects.

Hydrodensitometry

Underwater weighing at RV with estimation of RV by helium dilution. BD was determined by underwater weighing. A chair was suspended by a pulley system from an S1W Western Load Cell (Western Load Cell, Encino, CA), which was connected to a digital readout and an R-61 Rikadenki (Rikadenki Kogyo, Meguro-Ku, Tokyo, Japan) chart recorder. The FW-150K electronic balance (A&D Mercury Pty, South Australia, Australia), which was used for measuring nude mass to the nearest 20 g, and the load cell were calibrated over the physiological range of measurement by using masses that had been authenticated by the South Australian Office of Fair Trading. Five to ten underwater trials were conducted at RV, and the mean of the three largest masses was used to calculate BD. Water temperature was maintained in the range of 34.5-36.3°C.

The RV was estimated by helium dilution by using a 10-liter Stead-Wells modular spirometer and helium analyzer (Warren E. Collins, Braintree, MA). The constancy of the equipment's dead space was checked weekly, and the helium analyzer's accuracy was also monitored weekly by using gases of 0 and 10.0% helium. We used the manufacturer's modification of a procedure, which was outlined by Meneely and Kaltreider (15)
FRC (ml) <SC>atps</SC> = V (ml) × <FENCE> <FR><NU>%He<SUB>1</SUB> − %He<SUB>2</SUB></NU><DE>%He<SUB>2</SUB></DE></FR> </FENCE> − 125 ml
where V is the initial volume of the spirometer and tubing; %He1 is the percentage of helium before equilibration with the lung; %He2 is the percentage of helium after equilibration with the lung; and 125 ml is the correction for the dead space of the mouthpiece, the helium absorbed by the blood, and the respiratory quotient effect.

The expiratory reserve volume (ERV) was measured directly from the spirometer tracing. The FRC and ERV were converted to BTPS conditions, and the RV was calculated by subtraction (RV = FRC - ERV).

The RV was determined before and after the underwater trials, and the mean was used to calculate BD. The time interval between these two trials was at least 15 min. Measurements were conducted while the subject was immersed to neck level and in the same posture as during the underwater trials. BD was then calculated by using the formula of Goldman and Buskirk (11), except that no correction was applied for gas in the gastrointestinal tract. The %BF was then calculated from BD according to Brozek et al. (Ref. 3; %BF = 497.1/BD - 451.9).

Underwater weighing at approximately FRC with estimation of this lung volume by oxygen dilution. This procedure was identical to the preceding method except that the subjects were instructed to expire to a comfortable level (approximately FRC) for four immersed mass trials with each associated lung volume being measured by oxygen dilution immediately on surfacing. The mean of the three closest trials, which differed from one another by <1.0% BF, was used for all subsequent calculations.

Four polyethylene-lined foil bags were each filled with either 3.0 or 4.0 liters of pure oxygen and sealed with a stopcock. The subjects held their breath during the immersed mass measurements and on surfacing until the insertion of a modified mouthpiece. The stopcock was then opened, and the subject executed five deep breaths at a rate of 3 s per respiratory cycle before the stopcock was closed at the end of the fifth expiration. Care was taken to ensure that the bag was not completely evacuated. The percentage of nitrogen in the bag at equilibrium was then measured by a Hewlett-Packard 47302A Vertek (Andover, MD) nitrogen analyzer, which was checked daily for linearity and accuracy by using 0, 40.0, and 79.0% nitrogen gas standards. The gas volume in the lungs for each immersed mass trial was then calculated by using the Wilmore et al. (23) modification of the technique originally proposed by Rahn et al. (19) and Lundsgaard and Van Slyke (13)
Volume (ml) <SC>atps</SC> = <FR><NU>V<SC>o</SC><SUB>2</SUB> (%N<SUB>2eq</SUB> − 0.4)</NU><DE>80 − (%N<SUB>2eq</SUB> + 0.2)</DE></FR> − DS
where VO2 is the volume (ml) of O2 in the bag; %N2 eq is the percentage of N2 at equilibrium; DS (ml) is the dead space of the mouthpiece, which is 20 ml; 0.4 is the percentage of N2 impurities in the O2 rebreathing bag; 80 is the percentage of N2 in alveolar gas; and 0.2 is the correction for the percentage of N2 in alveolar gas (0.2% > %N2 eq).

The above volume was converted to BTPS conditions. This enabled the BD and %BF to be calculated as previously outlined.

Experimental Design

All experiments were conducted in the morning when the subjects were postabsorptive and euhydrated and had not exercised for 36 h. They were requested to walk for several minutes and then void in an attempt to eliminate any flatus in the gastrointestinal tract. Both of the following experimental treatments were administered on each of two separate visits within 3 days to minimize intrasubject biological variability, and the overall order was counterbalanced to control for any order effect: 1) measurement of RV via helium dilution both before and after the immersed trials at RV; and 2) expiration to a comfortable level (approximately FRC) with measurement of this gas volume by oxygen dilution each time an underwater mass was recorded.

Statistical Analysis

Data were analyzed by using interclass and intraclass correlation coefficients, technical errors of measurement (TEM) (7, 17), and dependent t-tests. A Bland-Altman plot, which was originally suggested by Oldham (18) but subsequently refined and popularized by Bland and Altman (2), was used to compare the two experimental treatments. The 0.05 level was used for all tests of statistical significance.


    RESULTS
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

Table 1 contains the raw data for the hydrodensitometric method, which involved the estimation of RV by helium dilution. These data yielded a TEM or SE of measurement, percent TEM, and intraclass correlation coefficient of 0.2% BF, 1.5%, and 0.999, respectively. Individual differences between the 2 days ranged from -0.6 to 0.5% BF with a SD of 0.4% BF. The means of the two data sets (day 1: 16.9 ± 9.2% BF; day 2: 16.9 ± 9.4% BF) were identical, and the dependent t-test was, therefore, not statistically significant (P = 0.81).

                              
View this table:
[in this window]
[in a new window]
  		Table 1.   Percent body fat data via the 2 hydrodensitometric methods

The RV by helium dilution data are presented in Table 2. Analyses of the means of the two trials on each day resulted in a TEM, percent TEM, and intraclass correlation coefficient of 51 ml, 3.7%, and 0.967, respectively. The corresponding statistics between trials on each day indicated greater reproducibility and reliability (day 1: 17 ml, 1.2%, 0.996; day 2: 23 ml, 1.6%, 0.994, respectively).

                              
View this table:
[in this window]
[in a new window]
  		Table 2.   Residual volume via helium dilution

The %BF data for the hydrodensitometric method, which used the oxygen dilution technique, are contained in Table 1, and the TEM, percent TEM, and intraclass correlation coefficient between the scores on days 1 and 2 were 0.4% BF, 2.3%, and 0.998, respectively. Individual differences between the 2 days ranged from -1.0 to 0.9% BF with a SD of 0.6% BF. As with the previous treatment, the means of the 2 days were identical (day 1: 16.9 ± 9.2% BF; day 2: 16.9 ± 9.5% BF) and yielded a nonsignificant dependent t-test (P = 0.93).

The 12 means of the two measurements for each treatment are graphed in Fig. 1. The interclass correlation coefficient was 0.999 with a SE of estimate of 0.4% BF. The regression line was superimposed on the line of identity because the slope and y-intercept of the former were 1.007 and -0.1% BF, respectively. Individual differences between the treatments ranged from -0.7 to 0.6% BF, and there were no differences between the means (P = 0.80) and variances (P = 0.97).


View larger version (22K):
[in this window]
[in a new window]
  		Fig. 1.   Percent body fat (%BF) comparison between the 2 hydrodensitometric methods. RV, residual volume; SEE, SE of estimate.

A Bland-Altman plot (Fig. 2) demonstrates that all 12 differences between the two treatments were within ±1.53 SD of the differences with no clear trend over the range of 3.3 to 33.5% BF. This latter point is supported by an interclass correlation of -0.188 (P = 0.56). Nevertheless, the variance for the differences between the two measurements using the oxygen dilution method (0.3% BF) was significantly greater (P < 0.01) than that using helium dilution (0.1% BF).


View larger version (15K):
[in this window]
[in a new window]
  		Fig. 2.   Bland-Altman plot of %BF differences between the 2 hydrodensitometric methods. <OVL>X</OVL>, mean.


    DISCUSSION
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

The major finding of this study is that there is no %BF difference between two hydrodensitometric methods, which involve: 1) estimation of RV by helium dilution before and after measurement of immersed mass at RV, and 2) measurement of immersed mass at a comfortable level of expiration with the associated gas volume estimated by oxygen dilution immediately on surfacing. Notwithstanding our small sample size of 12, the -0.03% BF difference between the two treatments is negligible, and the probability is 0.95 that the true difference between the means for the population is within the range of -0.03 ± 0.25% BF. Thomas and Etheridge (20) reported similar results for %BF via hydrodensitometry at RV and FRC when both volumes were measured by helium dilution at the time of immersed mass determination. They concluded that changes in lung volumes were accurately reflected by concomitant changes in immersed mass.

Whereas all subjects were specifically chosen for their ability to remain immersed at RV, this methodology may result in immersed masses at somewhat less than RV with consequent overestimation of %BF. Nevertheless, this does not appear to have occurred with our subjects because the precision of both methods was very high and they yielded almost identical results. However, this requirement that the immersed mass be recorded at RV is not made with our oxygen dilution method, which all subjects found to be less stressful than the helium dilution method because it did not involve expiration to RV. The oxygen dilution method is, therefore, more appropriate for testing subjects who find measurements at RV both uncomfortable and difficult. This applies particularly to older persons. Our oxygen dilution method also has an additional advantage in that the gas volume in the respiratory system during each immersed mass trial is measured instead of assuming that the immersed mass is determined at the same lung volume as that estimated separately by helium dilution.

Our intraclass correlation coefficients and TEMs emphasize that the RV can be measured with very high reliability and reproducibility by using helium dilution. The interday TEM of 51 ml is somewhat better than that of 84 ml reported by Meneely and Kaltreider (15), who originally proposed this method. However, it should be noted that our subjects were specifically chosen for their ability to execute an ERV and remain immersed at RV. They may, therefore, have been better at reproducing maximal efforts than the 22 normal subjects tested by Meneely and Kaltreider. Furthermore, analyzer technology has improved since 1949. A major reason for our lower intraday TEMs of 17 and 23 ml is that there was doubtless greater control over biological variability. Wilmore (22) also reported a low TEM of 28 ml for 195 men when he measured the RV via oxygen dilution.

It can be argued that the Rahn et al. (19) modification of the Lundsgaard and Van Slyke (13) method for the measurement of RV via oxygen dilution is not appropriate for the present study, which, according to the instructions given to the subjects, involved the estimation of the FRC. However, the six most divergent pairs of data sets in ascending order of difference for immersed mass and gas volume, together with the associated %BF values, are presented in Table 3. With the use of the lung volumes that were measured during the helium dilution tests, only 52% of the oxygen dilution trials for the 12 subjects occurred between the end-tidal expiratory level and RV. The six largest volume differences, which are presented in Table 3, ranged from 26.5 to 34.3% total lung capacity (TLC) [tidal volume (VT) = 24.8-32.4% TLC] for subject H and from 32.6 to 56.2% TLC (VT = 33.8-44.0% TLC) for subject L. These data demonstrate that there is close agreement between the two %BF scores for each of the six subjects despite very large differences for the gas volumes in the respiratory system. It would, therefore, appear that the methodology and formula are appropriate for measuring BD associated with a range of lung volumes (i.e., 21.8-56.5% TLC).

                              
View this table:
[in this window]
[in a new window]
  		Table 3.   The 6 largest intraday differences for immersed mass and gas volume in the respiratory system via oxygen dilution

A problem with dilution methods is that they do not measure the gas that is trapped behind closed airways. However, Dahlback and Lundgren (6) have demonstrated that the gas trapping that occurs during immersion is eliminated when the lung volume is increased to 38-43% vital capacity (VC). We were aware of this problem during the helium dilution method because the subjects were at resting VT during the 3- to 4-min equilibration period. They were, therefore, instructed to sigh midway through this equilibration period, and the second helium reading, which was used to calculate the FRC, was not recorded until reestablishment of a baseline on the spirometer chart paper after the first of the two inspiratory VC maneuvers. Furthermore, the five deep respirations during the oxygen dilution method involved the subjects operating at 57-83% VC. Hence precautions were taken to eliminate gas trapped behind closed airways during both helium and oxygen dilution.

Both methods that we compared required the measurement of mass in air, immersed mass, water temperature, and either the RV or the near end-tidal expiratory level (approximately FRC). Measurement of the first three variables was identical for both methods: the weighing scales and load cell were calibrated to within ±20 g over the physiological range of measurement, and the temperature sensor was authenticated against a National Association of Testing Authorities (Australia) certified instrument. Any measurement error due to these instruments would, therefore, be minimal and randomly distributed across the two methods. However, whereas both closed-circuit methods used the dilution principle, it is essential to review the assumptions and their associated errors when estimating the RV via helium dilution and the near end-tidal expiratory level (approximately FRC) by oxygen dilution.

Helium Dilution

It is logical that some helium is absorbed by the blood during the 3- to 4-min rebreathing procedure, but estimates of this volume vary. However, it is likely to be small, because helium has the lowest solubility coefficient in water at 37°C (Bunsen's absorption coefficient = 0.0085) of any inert gas (12). Meneely and Kaltreider (15) originally proposed that 10 ml of helium were absorbed by the blood during their 7-min rebreathing period, which was of longer duration than ours. Their later revised estimate (14) of 15 ml was associated with a FRC overestimate of 100 ml. However, both helium volumes are close to the limit of visual discrimination on the spirometer chart paper (1 mm = 41.45 ml).

Oxygen uptake normally exceeds carbon dioxide output in the lung. This so-called respiratory quotient effect, therefore, results in a higher helium concentration in the lung than in the spirometer. Assuming a respiratory exchange ratio of 0.8 and a FRC of 2.0 liters, Meneely et al. (14) calculated that this resulted in a FRC overestimate of 30 ml.

Another problem is that there is more nitrogen in the spirometer at the end of the test than at the beginning. The resultant effect on the thermal conductivity of the helium analyzer results in a FRC overestimate of 75 ml (14).

The sum of the three previous correction factors is 205 ml. However, plethysmography is the primary standard for the measurement of FRC. Zarins (25) has accordingly reported that the mean FRC for 125 healthy adults aged 20-80 yr was 3,065 ml via plethysmography and 3,050 ml by helium dilution when 100 ml were subtracted for helium absorption and the respiratory quotient effect. This now appears to be the authoritative correction factor (16).

Oxygen Dilution

The formula assumes that the volume of nitrogen in the lung-bag system does not change during mixing. Whereas the volume of nitrogen released from the blood into the alveoli has been estimated at 200-300 ml (4, 8) during the 7 min of the open-circuit method, this will be much less during the ~15 s of rebreathing that was used in our closed-circuit method. With the use of the assumptions of Rahn et al. (19) (cardiac output = 5 l/min; lung-blood nitrogen gradient = 350 mmHg; absorption coefficient of nitrogen in blood = 0.011), it can be calculated that only 6.3 ml of nitrogen would enter the lungs during the ~15 s of rebreathing. Christie (5) also calculated a low value of 10-12 ml during 20 s of hyperventilation. Both of the previous estimates affect the calculated gas volume by 9 and 17 ml, respectively, which translate to ~0.1% BF for the mean of our data. This error is very small, and it was, therefore, decided not to include a correction factor in our formula for blood nitrogen release.

Another error source is inconsistency of the percentage of nitrogen in the alveolar gas. Rahn et al. (19) argue logically for a constant of 80.0%, and this approximates the 79.7% that can be calculated from the alveolar carbon dioxide and oxygen tensions of 40 and 105 mmHg, respectively, which are quoted in popular physiology texts (10, 21). Furthermore, the error due to biological variability in healthy subjects is likely to be small, because a variation of 1.0% is equivalent to an error of 50 ml, which translates into an error of ~0.3% BF.

The 0.2% correction factor of Wilmore et al. (23) is presumably based on his previous work (22) in which, for each subject, he measured the percentage of nitrogen in alveolar gas before and after the subject rebreathed from the bag of oxygen in addition to the percentage of nitrogen in the bag at equilibrium.

Correction factors and assumed constants may be responsible for systematic differences between methods. However, whereas it is reassuring that virtually identical results were obtained for our two methodologies, which some may assume are therefore valid, an alternative interpretation is that the cumulative effects of each set of assumptions resulted in identical errors.

It has been hypothesized that the human body contains 2-3% essential fat (1). This is marginally below the scores of 3.1-3.5% BF for subject B, who can, therefore, be judged to possess negligible storage fat. However, the major limitation of hydrodensitometry is the assumption of 1.1000 g/cm3 for the FFM density. Subjects with greater FFM densities, which can be due to less than the assumed percentage of water and/or more than the assumed amount of bone mineral, will, therefore, have their %BF underestimated (24).

In summary, our data on a small sample of 12 healthy men indicate that the two following hydrodensitometric methods yield the same %BF values: 1) estimation of RV by helium dilution before and after measurement of immersed mass at RV, and 2) determination of immersed mass at a comfortable level of expiration (approximately FRC) with measurement of the associated gas volume by oxygen dilution. Whereas reliability and precision for both methods were very high, the subjects' comfort was enhanced during the oxygen dilution protocol because they did not have to exhale to RV during immersion. This would be a major advantage when older subjects are tested. The oxygen dilution method was also more expedient than that involving helium dilution.


    FOOTNOTES

The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.

Address for reprint requests and other correspondence: R. T. Withers, Exercise Physiology Laboratory, School of Education, The Flinders Univ. of S. Australia, GPO Box 2100, Adelaide 5001, S. Australia, Australia.

Received 5 January 1999; accepted in final form 6 November 1999.


    REFERENCES
TOP
ABSTRACT
INTRODUCTION
METHODS
RESULTS
DISCUSSION
REFERENCES

1.   Behnke, A. R. Anthropometric evaluation of body composition throughout life. Ann. NY Acad. Sci. 110: 450-464, 1963.

2.   Bland, J. M., and Altman D. G. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1: 307-310, 1986[ISI][Medline].

3.   Brozek, J., Grande F., Anderson J. T., and Keys A. Densitometric analysis of body composition: revision of some quantitative assumptions. Ann. NY Acad. Sci. 110: 113-140, 1963.

4.   Campbell, J. A., and Hill L. Concerning the amount of nitrogen gas in the tissues and its removal by breathing almost pure oxygen. J. Physiol. (Lond.) 71: 309-322, 1931.

5.   Christie, R. V. The lung volume and its subdivisions. I. Methods of measurement. J. Clin. Invest. 11: 1099-1118, 1932.

6.   Dahlback, G. O., and Lundgren C. E. G. Pulmonary air-trapping induced by water immersion. Aerospace Med. 43: 768-774, 1972[Medline].

7.   Dahlberg, G. Statistical Methods for Medical and Biological Students. London: Allen & Unwin, 1940, p. 122-132.

8.   Darling, R. C., Cournand A., Mansfield J. S., and Richards Jr D. W. Studies on the intrapulmonary mixture of gases. I. Nitrogen elimination from blood and body tissues during high oxygen breathing. J. Clin. Invest. 19: 591-597, 1940.

9.   Fidanza, F., Keys A., and Anderson J. T. Density of body fat in man and other mammals. J. Appl. Physiol. 6: 252-256, 1953[Free Full Text].

10.   Fox, S. I. Human Physiology. Dubuque, IA: Wm. C. Brown, 1993, p. 427.

11.   Goldman, R. F., and Buskirk E. R. Body volume measurement by underwater weighing: description of a method. In: Techniques for Measuring Body Composition; proceedings of a conference, Quartermaster Research and Engineering Center, Natick, Massachusetts, January 22-23, 1959, edited by Brozek J., and Henschel A.. Washington, DC: National Academy of Sciences-National Research Council, 1961, p. 78-89.

12.   Lawrence, J. H., Loomis W. F., Tobias C. A., and Turpin F. H. Preliminary observations on the narcotic effect of xenon with a review of values for solubilities of gases in water and oils. J. Physiol. (Lond.) 105: 197-204, 1946.

13.   Lundsgaard, C., and Van Slyke D. D. Studies of lung volume. I. Relation between thorax size and lung volume in normal adults. J. Exp. Med. 27: 65-86, 1918.

14.   Meneely, G. R., Ball C. O. T., Kory R. C., Callaway J. J., Merrill J. M., Mabe R. E., Roehm D. C., and Kaltreider N. L. A simplified closed circuit helium dilution method for the determination of the residual volume of the lungs. Am. J. Med. 28: 824-831, 1960.

15.   Meneely, G. R., and Kaltreider N. L. The volume of the lung determined by helium dilution. Description of the method and comparison with other procedures. J. Clin. Invest. 28: 129-139, 1949.

16.   Miller, W. F., Scacci R., and Gast L. R. Laboratory Evaluation of Pulmonary Function. Philadelphia, PA: Lippincott, 1987, p. 145.

17.   Mueller, W. H., and Martorell R. Reliability and accuracy of measurement. In: Anthropometric Standardization Reference Manual, edited by Lohman T. G., Roche A. F., and Martorell R.. Champaign, IL: Human Kinetics, 1988, p. 83-86.

18.   Oldham, P. D. A note on the analysis of repeated measurements of the same subjects. J. Chron. Dis. 15: 969-977, 1962[ISI][Medline].

19.   Rahn, H., Fenn W. O., and Otis A. B. Daily variations of vital capacity, residual air, and expiratory reserve including a study of the residual air method. J. Appl. Physiol. 1: 725-736, 1949[Free Full Text].

20.   Thomas, T. R., and Etheridge G. L. Hydrostatic weighing at residual volume and functional residual capacity. J. Appl. Physiol. 49: 157-159, 1980[Abstract/Free Full Text].

21.   Vander, G., Sherman J., and Luciano D. Human Physiology: The Mechanisms of Body Function. Boston, MA: WCB/McGraw-Hill, 1998, p. 478.

22.   Wilmore, J. H. A simplified method for determination of residual lung volumes. J. Appl. Physiol. 27: 96-100, 1969[Free Full Text].

23.   Wilmore, J. H., Vodak P. A., Parr R. B., Girandola R. N., and Billing J. E. Further simplification of a method for determination of residual lung volume. Med. Sci. Sports Exerc. 12: 216-218, 1980[ISI][Medline].

24.   Withers, R. T., LaForgia J., Pillans R. K., Shipp N. J., Chatterton B. E., Schultz C. G., and Leaney F. Comparisons of two-, three-, and four-compartment models of body composition analysis in men and women. J. Appl. Physiol. 85: 238-245, 1998[Abstract/Free Full Text].

25.   Zarins, L. P. Closed circuit helium dilution method of lung volume measurement. In: Pulmonary Function Testing Guidelines and Controversies. Equipment, Methods, and Normal Values, edited by Clausen J. L.. New York: Academic, 1982, p. 129-140.

J APPL PHYSIOL 88(4):1175-1180
8570-7587/00 $5.00 Copyright © 2000 the American Physiological Society


This article has been cited by other articles:


Home page
 Br. J. Sports. Med.Home page
G J Slater, G M Duthie, D B Pyne, and W G Hopkins
Validation of a skinfold based index for tracking proportional changes in lean mass.
Br. J. Sports Med., March 1, 2006; 40(3): 208 - 213.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
G. E. van der Ploeg, R. T. Withers, and J. Laforgia
Percent body fat via DEXA: comparison with a four-compartment model
J Appl Physiol, February 1, 2003; 94(2): 499 - 506.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Clin. Nutr.Home page
D. A Fields, M. I Goran, and M. A McCrory
Body-composition assessment via air-displacement plethysmography in adults and children: a review
Am. J. Clinical Nutrition, March 1, 2002; 75(3): 453 - 467.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (9)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by van der Ploeg, G. E.
Right arrow Articles by Crockett, A. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by van der Ploeg, G. E.
Right arrow Articles by Crockett, A. J.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online