9.2: Introduction

The human heart demonstrates remarkable efficiency in its pumping capacity. With an average heart rate of 75 beats per minute, it carries out approximately 108,000 contractions every day, exceeding 39 million beats annually, and 3 billion beats over a 75-year lifespan. In each heartbeat cycle, every heart chamber propels around 70 mL of blood in a resting adult. The overall output accumulates to a rate of 5.25 liters of blood per minute and an impressive 14,000 liters per day. Across a year, this cumulative output amounts to an astonishing 10,000,000 liters or 2.6 million gallons of blood. This immense quantity of blood flows through a network of vessels extending approximately 60,000 miles throughout the body.¹

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