So the blood comes out of the heart, into the arteries, through a maze of capillaries and back to the heart.
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.
