Mj. Turner et al., THE EQUILIBRIUM CO2 REBREATHING METHOD DOES NOT AFFECT RESTING OR EXERCISE BLOOD-PRESSURE, Medicine and science in sports and exercise, 28(7), 1996, pp. 921-925
The equilibrium CO2 rebreathing technique has been widely used for the
noninvasive determination of cardiac output. Recently, several invest
igators have used this technique in conjunction with auscultatory bloo
d pressure measurements to calculate total peripheral resistance. To e
xamine the validity of this approach, we attempted to determine whethe
r the CO2 rebreathing procedure has a significant effect on blood pres
sure. The participants in the present study were 10 male subjects, 24
+/- 1 yr of age (mean +/- SE). Each subject performed two trials-one w
ith CO2 rebreathing and one without. Both trials consisted of three st
ages (rest, 25%, and 50% VO2peak), each stage lasting 15 min. During t
he rebreathing trial, the CO2 rebreathing technique was administered a
t 10 min into each stage. There were no statistically significant diff
erences in the heart rate, systolic blood pressure, diastolic blood pr
essure, and mean arterial blood pressure responses between the two tri
als. These results indicate that the equilibrium CO2 rebreathing techn
ique does not alter auscultatory blood pressures at rest and during ex
ercise up to intensities of 50% VO2peak.