# Science Questions

## How quickly does a blood cell circulate?

Sat, 28th Apr 2012

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### Question

How long does it take a drop of blood to do a full circuit of the system?

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Richard Almand (from New Zealand)

Diana -   I think the answer is going to be about a minute for most people.

You have about 5 litres of blood in your body (at least most people do) and the average heart pumps about 70 ml of blood out with each beat.

The next bit is going to depend on your resting heart rate.

I think most people have an average resting heart rate of about 70 beats a minute (somewhere around there).  So, if you multiply the amount of blood that the heart can pump by the number of beats in a minute, you actually get about 4.9 litres of blood, which is almost your whole body’s worth of blood.

So, in a minute, you will pump the entire blood volume around your body.

#### Make a comment

The time that I've consistently seen is about 20 seconds. Lmnre, Sun, 29th Apr 2012

Depends what route it takes and how active the person is at the time.

but total blood volume is ~5 liters, flow rate in aorta at rest is ~100cm3 per second: 5000/100 = 50 seconds RD, Sun, 29th Apr 2012

Indeed. The travel time is affected by route. All blood goes from heart -> lungs -> heart -> body -> heart -> lungs....
Now if the body portion of the route is your foot, it'll take longer to circulate compared to the body portion of the route being your coronary arteries. Nizzle, Mon, 30th Apr 2012

What!!! Seth, Fri, 4th Apr 2014