Heart & Blood Pressure
It is a muscle about the size of your fist that weighs approximately one pound and it is located behind and slightly to the left of the breastbone. The heart pumps about 5 quarts (4.7 liters) of blood every minute or 1800 gallons (6768 liters) of blood every day. A healthy heart beats steadily and rhythmically at a rate of about 60 to 100 beats per minute when at rest (normal sinus rhythm). During strenuous exercise, the heart can increase the amount of blood it pumps up to four times the amount it pumps at rest, within only a matter of seconds.