Heart Health: Strength, Endurance, and Control
- Sep 7, 2023
- 6 min read
Updated: Mar 27, 2024
In our previous posts, we have discussed heart rate variability (HRV) as an indicator of heart health. And we have discussed various means of maximizing heart health as well, comparing low, medium, and high Intensity Continuous Training (LISS,MICT, HICT) to High Intensity Interval Training (HIIT). But, what exactly is heart health?
Heart Health: Strength, Endurance, and Control
In evaluating the health of the heart, one can consider many aspects: The following is not an exhaustive list, but certainly a broad and appropriate starting point.
One consideration in respect to heart health is the strength of the heart itself. The heart is a muscle, and although it does have some characteristics that make it different than the skeletal muscles that most people are familiar with, it also does possess some similar characteristics. Just like other muscles, the heart must be strong enough to function well. If the heart is strong, it will theoretically be able to push out greater amounts of blood with each contraction. This is referred to as cardiac output. A good cardiac output (good cardiac strength) is associated with good cardiovascular health.
A second way to assess heart health would be based on how frequently the heart needs to pump in order to get adequate blood supply to all of the tissues. This would be one's heart rate or pulse, and is often associated with cardiac output. In other words, if the heart is able to eject a sufficient volume of blood with each contraction (cardiac output), it does not need to contract as frequently (heart rate or pulse) to get blood to the tissues. Pulse rate can also be impacted by other factors such as high blood pressure (resistance in the vessels), stress, and changes associated with age, to name just a few.
Cardiac Strength and Endurance
So, in evaluating heart health, cardiologists traditionally look at factors such as cardiac output and heart rate because they can be an indication of the power of the heart (strength) and the strength of the heart over time (endurance). In general, a healthy heart has to be strong enough to pump a sufficient volume of blood with each contraction to meet the body's demand, and a healthy heart has to be able to tolerate an increased heart rate and/or force for extended periods when the task at hand demands. In other words, the heart has to be strong, and it has to have good endurance.
Cardiac Control
A third, less traditional way, of assessing heart health is evaluating heart rate variability (HRV). HRV refers to very subtle changes in the rate of the heart, changes so subtle that they cannot be detected by manually tracking the pulse. HRV can be detected and monitored per EKG or biofeedback devices. HRV is not an indication of the heart's strength or endurance, but rather, it is an indicator of the heart's control, its ability to regulate and adapt to stress. Good HRV is a sign of cardiac coordination and fine tuning. It means that the central nervous system and heart are working together to achieve a coordinated cardiac response to stress so that the heart can subtly increase its rate when there is a need, and also easily decrease its rate to allow greater cardiac rest and recovery.
Understanding Heart Health by Comparison to Skeletal Muscle
The heart is a muscle and shares some similarities to other skeletal muscles, the muscles that move our arms, legs, head and trunk. Skeletal muscle, is "volitional", or under our control. The fibers in cardiac muscle are arranged differently than those in skeletal muscle, and are not under our conscious control, or volitional. Cardiac muscle's control is exercised automatically, without us having to think about it, by the central nervous system (the brain and spinal cord). (There are actually mountains of research that show that we can actually influence the function of the heart and other processes controlled by the central nervous system, but that is fodder for another post!) In general, though, the heart will beat on "auto-pilot" our entire lifetime without us having to think about controlling it.
For the sake of comparison, however, let's compare the heart to our skeletal muscle, which is under our control. I have a 30 year history of work in the medical field as a physical therapist, and as a physical therapist, if I were to evaluate skeletal muscle and performance, I would evaluate and consider a few things. So, let's use the example of a pitcher coming to me with complaints of difficulty in throwing a fast ball...Let's talk about the how a physical therapist might evaluate the health, or function of skeletal muscle:
1. First, one would likely evaluate strength: Does this pitcher have sufficient strength in the muscles of the shoulder, forearm, wrist, hand, trunk, and lower extremity to be able to throw a ball ? If the pitcher had torn the rotator cuff muscles of the shoulder, it stands to reason that he/she would likely have significant difficulty in effectively throwing a ball.
2. One might also evaluate muscular endurance: does the pitcher have sufficient strength to pitch a ball effectively over time or does his/her strength wain very quickly? Does performance decline over a short period of time?
3. The third way one might evaluate the pitcher's performance would be in respect to coordination: perhaps the pitcher is able to throw the ball very rapidly and forcefully (strength), and can do so for 9 innings (endurance), but he/she cannot very effectively fine-tune the contractions and the timing of all of the muscle necessary to throw a fast ball (coordination).
If a college scout was recruiting pitchers, I'm going to guess that they would not be very impressed by a pitcher who was powerful enough to throw 100mph fast balls for 9 innings if the pitcher couldn't ever get the ball over the plate! In other words, strength and endurance are important, but the ability to fine-tune and coordinate movement is essential for good function!
Coordination of the Heart, Fine-Tuning, and Heart Rate Variability
The same can be said about heart function: strength and endurance of the cardiac muscle is important, but coordination and fine tuning is also essential! The most traditional means recommended by organizations such as the American Heart Association to train the heart (as discussed above), however, are generally focused on improving strength and endurance. The recommendations are to work toward being able to perform vigorous activity (cardiac strength) and maintain that level of activity over time (cardiac endurance). As far as I am aware, traditional recommendations for maintaining or achieving heart health do not include strategies that address cardiac coordination. Are we missing an emphasis on training the coordination of the heart?
Coordination as related to pitching a ball is very easy to define: Can the pitcher deliver the ball at a rapid enough velocity, and in a very defined location (over the plate), so that his/her opponent might have difficulty in connecting with the ball? That would clearly be a coordinated and functional effort. But what would coordination of the heart muscle entail? Perhaps Heart Rate Variability (HRV) gives us a lens for evaluating the fine-tuning of the heart's activity, as it is an indication of how effective the heart is in coordinating subtle adjustments to stress!
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Disclaimer: This BLOG is for Educational Purposes, Only. This information provided is educational and informational in nature and is made only as general information. The information does not establish a patient-provider relationship, establish a standard of care, or offer medical, dietary, or therapeutic care, advice, opinion, diagnosis, or treatment. This information does not replace independent professional or medical judgment and should not be relied upon as medical, psychological, or other professional advice of any kind or nature whatsoever. This information should not be used for diagnosing or treating any mental or physical health problem or disease. You are solely responsible for any action taken based on your interpretation of this information and you are responsible for your own health care decision-making by obtaining any necessary consultations with appropriately licensed health care professionals such as physicians and psychologists.
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