What is the cardiac cycle duration in seconds?

The cardiac cycle duration is approximately 0.8 seconds in a resting adult. This duration encompasses the sequence of events that occur from the beginning of one heartbeat to the beginning of the next, including both the systolic (contraction) and diastolic (relaxation) phases of the heart.

During this cycle, the heart chambers alternate between filling with blood and pumping it out to the body and lungs. Specifically, the cycle consists of about 0.3 seconds for systole (when the heart muscle contracts) and approximately 0.5 seconds for diastole (when the chambers fill with blood).

An average heart rate of about 75 beats per minute leads to this duration, as the time taken per beat can be calculated from the heart rate (60 seconds divided by the heart rate). Therefore, at 75 beats per minute, each beat takes about 0.8 seconds, making it the most representative duration for the cardiac cycle in a healthy adult at rest.

Understanding this timing is crucial for students in health sciences, as it reflects normal cardiac function and can be used as a baseline for identifying arrhythmias or other cardiac conditions.