What happens to the heart rate when you take a deep breath?

Change in heart rate with breathing

Change in heart rate with breathing: Heart rate increases while breathing in and decreases while breathing out. This is to compensate for the decreased left ventricular output while breathing in. During inspiration, more blood gets pooled in the lungs so that left ventricle gets less blood to pump out. By increasing the heart rate with a reflex mechanism, body maintains the cardiac output. Cardiac output is the product of heart rate and the volume of blood pumped out by the heart in a single beat. In contrast, left ventricular output is higher in expiration and heart rate lower. Corresponding to this the volume of pulse will be higher in expiration and lower in inspiration. Same change can be noted in a blood pressure tracing using a small tube inserted into the radial artery.


Inspiration: Breathing in – lungs expand
Expiration: Breathing out – lung volume decreases
Left ventricle: Lower left muscular chamber of the heart
Cardiac output: Volume of blood pumped out by the heart in a minute
Stroke volume: Volume of blood pumped out by the heart in a single beat
Radial artery: Blood vessel carrying oxygenated blood to the forearm
Cannula: Small tube inserted into a blood vessel

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