Re: How do i tell an athlete's heartbeat from a sedentary's?

Hello Jeremy,

Thank you for your interesting question about heart sounds.

I have found a web site that may interest you in listening to heart sounds, 
it can be found at http://www.wilkes.med.ucla.edu/inex.htm.  This site 
includes normal heart sounds and examples of many different types of heart 
murmers.  However it does not give any differences between the heart sounds 
of the trained athlete and the sedentary.  I have been unable to find 
anywhere that mentions differences between the heart sounds of these 
different groups of people and there may be no difference between the two. 
 The heart sounds are made as the valves in the heart close during the 
different phases of the cardiac contraction cycle.  The first heart sound 
occurs as the ventricles of the heart contract, which closes the mitral and 
tricuspid valves, shutting off the blood flow to the atria.  The second 
heart sound occurs as the ventricles start to relax and the aortic and 
pulmonary valves close stopping regurgitation of ejected blood back into 
the heart.  If the valves are working correctly then these sounds should 
sound the same in both the athlete and the untrained individual.  There are 
two further heart sounds, which are much more difficult to detect, the 
third heart sound occurs  shortly after the second and is associated with 
the start of the filling of the ventricles  and the fourth heart sound is 
from the contraction of the atria just before the first heart sound.  When 
sounds are heard in addition to the normal heart sounds these are called 
heart murmers and are an indication of a disease state.   Therefore 
differences in heart sounds are used to diagnose disease states rather than 
to distinguish between athletes and untrained individuals.

To distinguish between bradycardia and the slow heart rate of a trained 
athlete you could measure the heart rate during exercise such as on a 
treadmill.  The trained athlete should have a very high exercise tolerance 
level and be able to achieve normal elevated heart rates.  (Estimated 
maximum heart rate = 220 - age.  A trained athlete should be able to 
maintain exercise level at 70-80% of this maximum heart rate). However if 
the individual has bradycardia then they will be less able to perform in 
the exercise and may not be able to achieve 70% of the estimated maximum 
heart rate.

I hope that this answers your question and thank you for your interest.

Regards

Dr. David Burton