# How do you calculate the volume of blood your heart pumps in an hour?

Apr 9, 2016

$T = 60 \cdot V \cdot r$, where $T$ is the total in an hour, $60$ due to minutes in an hour, $V$ is the volume of blood per beat, and $r$ is the resting heart rate in beats per minute.

#### Explanation:

A human (~adult) heart pumps between 60 and 90ml of blood each contraction, so a good average would be anywhere from $70$ to $80 m l$ to use in calculation. I'll use $75$, though it would vary with age, person, and instantaneous exertion, presumably.

Take your resting heart rate in beats per minute. Take it a few times and find the average for the most accurate value.

Do the calculation

$T = 60 \cdot V \cdot r$,

where $T$ is the total blood pumped, $V$ is the volume per pump ($75$ in this approximation, $r$ is resting heart rate and $60$ is for the number of minutes you want.

With units, this is

$T m l = 60 \min \cdot V \frac{m l}{b e a t s} \cdot r \frac{b e a t s}{\min}$,

so the $\min$ and $b e a t s$ units cancel, leaving only $m l$.

Say your resting heart rate is $80 \frac{b e a t s}{\min}$, then the total blood pumped in one hour is approximately

$T \approx 60 \cdot 75 \cdot 80 = 360 , 000 m l = 360 L$