[Human body volume measurement by sulfur hexafluorde-dilution method and its application to human body composition assessment].

The absolutely accurate measurement of adiposity in a living organism is undoubtedly difficult. Although a number of methods have been developed, none has been proven to be both theoretically and empirically an unquestioned validating criterion method for the estimation of human body composition. In the present study, a new method was introduced that is rapid, safe, and relatively simple to administer and has the added advantage of not requiring a measurement of the underwater weight. The procedure involves the direct measurement of body volume by applying a sulfur hexafluoride (SH)-dilution method with the subject only standing in a 375-1 closed chamber (Shimazu BSF-100) that is filled with air and 0.26 liters of SH. Results indicate that body volume (r = 0.998) and body density (r = 0.819) measured by the SH method were highly correlated to those determined by underwater weighing. Reproducibility of body volume was found to be almost perfect (i.e., 0.995) with the regression coefficient of 1.03 and the intercept of -1.5. Variability (CV = 0.7%) in body volume of a 45-year-old reference man measured by SH method was very similar to variation (CV = 0.6%) in mass volume of the 60-1 prototype. The calculated percent body fat (r = 0.851) and fat-free mass (0.962) with some correction of body density were also highly correlated to those determined by underwater weighing. We suggest that SH method may be useful for assessment of human body composition.