One‐minute heart rate variability – an adjunct for airway obstruction identification

Heart rate variability (HRV) reflects cardiac and autonomic nervous system activity. It is usually measured over a relatively prolonged period and presented using multiple parameters. Here, we studied rapid HRV changes during airway obstruction using a short (1 min) sampling window. Forty healthy volunteers underwent a trial of obstructed breathing. Heart rate was recorded during three consecutive sets comprised of 1‐min control followed by 1 min of obstructed breathing, with 1 min of rest between sets. Time and frequency domain analysis were used to compare HRV during control versus obstructed breathing. Compared with control, HRV intensely increased during obstructed breathing: R‐R intervals (time between consecutive R waves) standard deviation increased from 65 to 108 msec (P