Cardiac Output

Cardiac Output

General Overview

• Cardiac Output is the amount of blood the heart pumps each minute.
• It plays a key role in the efficiency of the body’s circulatory system.

Components

• Cardiac output is determined by two factors: Heart Rate (HR) and Stroke Volume (SV).
• Heart Rate is the number of times the heart beats per minute.
• Stroke Volume is the volume of blood pumped from the left ventricle out to the body each heartbeat.

Calculation

• Cardiac Output (CO) is calculated using the formula: CO = HR x SV
• Therefore, if a person’s heart rate was 70 beats per minute, and stroke volume was 70 millilitres, their cardiac output would be 4900 millilitres, or 4.9 litres per minute.

Regulation

• The body regulates Heart Rate and Stroke Volume to change the Cardiac Output in response to varying demands.
• During exercise, the body needs more oxygen, so Heart Rate and Stroke Volume increase, thus increasing the Cardiac Output.

Impact on Performance

• Athletes typically have a lower resting heart rate but a higher stroke volume, resulting in a higher cardiac output.
• This allows them to deliver more oxygen to their active tissues, enhancing their performance.
• Training can improve an individual’s cardiac output by lowering heart rate and increasing stroke volume.

Bear in mind: A higher Cardiac Output typically equates to better fitness and performance!