The so-called respiratory resistance (RR) was measured on rural inhabitants with the RR meter (MZR-4000), which is based on oscillation technique and pressured sine wave were fixed to 3Hz. The measured values from 434 normal males and 704 normal females were studied with the following results ;
1) RR (more rightly to be called 3Hz respiratory impedance), showed positively skewed asymmetric distribution. The mean (X) and standard deviation (SD) for age group of 40-64 years old was 3.16±0.835 in males and 3.61±0.852 in females (in cmH2O/l/sce). The difference between males and females was statistically significant (P<0.01).
2) RR was significantly correlated with FVC, FEV1.0 and Wright's PFR (P<0.01). And it was also correlated significantly but lower than with FVC, FEV1.0 and PFR, with age and height (P<0.01).
3) When RR 4.0 for males and 4.5 for females were provisionally taken as the screening levels on the basis of X+1SD, RR of those with obstructive impairments were, in comparison with those levels, shown as follows : In pulmonary emphsema, RR inexceptionally exceeded the level, while in bronchial asthma and chronic bronchitis (except during attack), it is sometimes below the level, though they can all be distinguished by it with the additional findings of % FEV 1.0 or PFR.
Also normal subjects occasionally gave RR which is above the screening levels, but more than half of them showed one or more of FVC, FEV1.0 and PFR to be low. And among obese subjects, the incidence rate of low level RR was significantly decreased (P<0.05).
4) The time necessary for RR measurement of repeated three consecutive tests was about 3-4 minutes per person.