The Heart Rate Response to Deep Breathing (HRDB) is a commonly used measure of Heart Rate Variability. Inspiration leads to an increase in heart rate, and conversely expiration leads to a decrease in heart rate. HRDB is the simplest and most widely performed measure of autonomic nervous system function.
HRDB is a measure of cardiovagal activity, and a measure of the parasympathetic branch of the autonomic nervous system.

The HRV Acquire combines ECG monitoring, chest expansion, valsalva device and cue, and breathing cue in one patient interface. While programmable to your protocol for number and duration of breathes, it defaults to the standard 8 breathes at a rate of 6 breathes/minute. WR TestWorks software marks the beginning and ending of each set of breathes automatically, keeping the focus on the patient and allowing the technician to provide coaching for the best possible effort.