Data on reference values of total respiratory resistance (R(int)) in h
ealthy people are limited. The aim of this study was to examine the re
lationship between R(int) and gender, height, weight, age and smoking
habits. The instrument used was the Jaeger Pneumoscope with a flow int
erruption device. The method is based on transient interruption of air
flow at the mouth for a brief period during which alveolar pressure eq
uilibrates with mouth pressure. Measurement of mouth pressure is used
to estimate alveolar pressure prior to interruption. The ratio of this
to the flow prior to interruption gives airway resistance. The R(int)
data were correlated with height, weight, age, gender and smoking hab
its in 172 healthy subjects. They had a normal lung function (VC, FEV(
1)) and no signs of pulmonary disease. The important determining facto
r for the value of the R(int) were height and age. The mean R(int) of
172 subjects was 0.38 +/- 0.17 kPa.1(-1) s. The average within-subject
variability of repeated measurements of R(int) expressed as coefficie
nt of variation was 14.4 +/- 6.9%. Reference equation and normal value
s for R(int) in a healthy population are related to height and age. Th
e measurements were obtained with a commercially available interruptio
n technique.