Measurement of R-R Interval Variations under Deep Breathing Load in Healthy Persons

Abstract

In order to examine the effect of breathing depth and respiratory minute rate on R-R interval variations during deep breath, standard deviation (SD), coefficient of variation (CV) of R-R interval and a difference between the maximum heart rate and the minimum heart rate (DHR) were measured. Compared with the static condition, CV was increased by 27.3% with the half breathing depth, and by 101.8% with the maximum breathing depth. DHR was not changed with the half breathing depth, and that was increased by 25.4% with the maximum breathing depth. There was a significant (p<0.001) difference in CV and SD of healthy subjects between 6 times/min of respiratory minute rate and the static condition, but not between 12 times/min of respiratory minute rate and the static condition. SD and CV of patients with SMON at 12 times/min of respiratory minute rate were significantly (p<0.05) lower than those at static condition. © 2000, The Society of Physical Therapy Science. All rights reserved.