When is it normal to hear the S3 heart sound?

The S3 heart sound, often referred to as a third heart sound, can be considered a normal finding in certain demographics, particularly among younger individuals and well-conditioned athletes. The presence of an S3 in these populations is typically attributed to increased efficiency in heart function and greater diastolic filling due to the heart's strong ability to accommodate larger volumes of blood with each heartbeat.

In individuals under 40, especially athletes, the heart usually has enhanced compliance and a well-functioning pump mechanism, allowing for the normal physiological occurrence of this sound. The S3 is often heard as a result of rapid ventricular filling during early diastole, which is common among those whose hearts are healthy and functionally robust.

In contrast, the other scenarios presented do not align with the typical understanding of when the S3 heart sound might be considered normal. Hearing it in individuals over 60 or those with heart conditions could indicate underlying issues, making its occurrence potentially abnormal in those contexts. Likewise, while the S3 may occasionally be heard in everyone during vigorous exercise due to physiological changes, it is not universally considered "normal" in that scenario outside of specific populations. Thus, the reference population of younger individuals and athletes aligns most accurately with the normalcy of hearing an S