How long does it take for blood to go all the way around the body?

Blood travels at three feet per second when it leaves the heart, but it slows down as it gets into smaller arteries and capillaries. It takes a minute to get around the body.

Heart pumps about 70 ml of blood out with each beat.70 beats a minute,So,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.



 Five quarts of blood per minute are transported around the body.

How long does the round trip take? A typical human body contains 5.6 liters (6 quarts) of blood. According to this page “The heart pumps about 2,000 gallons (7,571 liters) of blood a day through its chambers.”

2,000 gallons per day works out to 83 gallons per hour, or nearly 6 quarts per minute. So it takes about one minute for blood to make the round trip to the heart. If you are running fast, your heart is pumping more blood so the time would be less.

Ingrid Spielman, Material Engineer

There is roughly 5L of blood in the body, so we can say that a single cycle is when 5L of blood has passed completely through the body.

Blood Pressure
'average' resting blood pressure = 1/3 systolic + 2/3 diastolic = 1/3(115) + 2/3(75)
(this is because we can say that the heart beats 1/3 of the time and 2/3 of the time the arteries apply a force to move the blood)

Easy calculation #1:
resting heart rate is about 60bpm  but walking is around 80bpm
How much blood does a heart pump per beat? 
(70ml/heartbeat)*(70bpm)*(24hrs/day)*(60min/hr)*(1/1000 L/ml) = 7,056 L per day
(7,056 L/day)/(5L/Cycle) = 1,411 cycles per day


Easy calculation#2:
Go: http://users.rcn.com/jkimball.ma...

 5,600 ml/min total blood flow (I don't know how they got that value)
5,600*(24 hours/day)*(60 min/hour)* (1/1000 L/ml)= 8,064 L per day
8,064/5 = 1,612 cycles per day
You may want to do some weighted average of resting and non-resting blood flow to come up with a better answer. 

Complicated Calculation#3:
Poiseuille's Law (http://hyperphysics.phy-astr.gsu...)

We would use this because our flood flows through tube-like vessels in the body. 

• pi = 3.14
• the average radius of our vessels is on the order of capillary size which is roughly 5*10^-4cm. Capillaries limit blood flow since they are the smallest vessels in the body. They are about 5-10 micrometers in diameter. http://biology.about.com/od/anat...

HOWEVER, our body is like a giant circuit so all resistors are additive. This means that it is possible that the diameter should be determined over the entire range of vessel diameters in the body

• blood viscosity is 0.004  Pa.s  http://en.wikipedia.org/wiki/Blo...
• We have about 10^10cm distance to travel in blood vessels (60,000 mile)http://users.rcn.com/jkimball.ma...

AGAIN, this estimation may be incorrect because the blood may not travel through all blood vessels before going back to the heart. I'm not sure what parts should be added in series or parallel. 

Q = 3.14*(5*10^-4cm)^4*(120 mm Hg) / (8*(0.004  Pa.s)*(10^10cm))
Q = 7.36*10-20 cm^3/s ~ 10^-22 L/s
24hrs/day*60min/hr*60sec/min = 86400 sec/day
86400 sec/day *  10^-22 L/s = 8.64*10^-18 L per day