What does heart rate measure?

What does heart rate measure?

• A. Stroke Volume
• B. Cardiac Output
• C. Heart Rate
• D. Ejection Fraction

Answer: (C)

Heart rate is the number of times the heart beats per minute, i.e., how often the heart contracts to pump blood. It tells you the frequency of heart activity but not the amount of blood moved per beat or the total blood flow. Stroke volume is the amount of blood ejected with each beat, while ejection fraction is the percentage of blood in the ventricle ejected with each beat. Cardiac output combines both rate and volume (heart rate × stroke volume) to describe total blood pumped per minute. So heart rate specifically measures how often the heart beats each minute. For example, at 70 beats per minute with a stroke volume of 70 mL, cardiac output would be about 4.9 liters per minute.

Heart rate is the number of times the heart beats per minute, i.e., how often the heart contracts to pump blood. It tells you the frequency of heart activity but not the amount of blood moved per beat or the total blood flow. Stroke volume is the amount of blood ejected with each beat, while ejection fraction is the percentage of blood in the ventricle ejected with each beat. Cardiac output combines both rate and volume (heart rate × stroke volume) to describe total blood pumped per minute. So heart rate specifically measures how often the heart beats each minute. For example, at 70 beats per minute with a stroke volume of 70 mL, cardiac output would be about 4.9 liters per minute.