Why is it better to have a lower resting heart rate?
Resting heart rate definition
A lower resting heart rate is a clear sign of good cardiovascular health and is associated with benefits that contribute to longevity and overall well-being. To understand why a lower heart rate is advantageous, we need to delve deeper into the functioning of the heart and the circulatory system.
The resting heart rate is the number of times your heart beats per minute while you are at rest, typically measured after waking up in the morning before any physical activity. Although the optimal resting heart rate is not definitively known, a lower resting heart rate is generally considered better. Typically, a normal resting heart rate ranges between 50 and 90 beats per minute, depending on numerous factors, including a person's anthropometric data (such as height and weight), gender, age, and physiological characteristics. The majority of healthy adults have a normal resting heart rate ranging from 60 to 70 beats per minute. However, athletes and individuals in excellent physical condition may have a resting heart rate as low as 40 to 60 bpm.
Understanding heart function
In healthy individuals, heart rate and its variability are affected by various internal and external factors. Internal factors include circadian rhythm and metabolic rate, while external factors include physical activity, smoking, eating, emotional stress, and medication use primarily affecting the nervous system itself.
The heart rate is normally regulated by a balance between two branches of the autonomic nervous system: the parasympathetic and sympathetic nervous systems. The parasympathetic system, primarily through the vagus nerve, acts like a brake on the heart, slowing it down. The sympathetic system, on the other hand, acts like an accelerator, increasing the heart rate.
The heartbeat is regulated by a specialized group of cells known as the sinoatrial node, which serves as the heart's natural pacemaker, located within the heart. This pacemaker is controlled by the body's autonomic nervous system, with both parasympathetic and sympathetic nerves being responsible for its regulation. The cardiac branch of the vagus nerve is primarily responsible for regulating heart rate at rest. If the cardiac nerves are completely blocked, the parasympathetic "braking" effect is removed, causing the heart to set its own pace without nervous system influence.
Another key concept is cardiac output (CO), the amount of blood the heart pumps per minute, expressed in liters per minute. Cardiac output is determined by the equation CO = HR * SV, where HR is the heart rate, expressed in beats per minute, and SV is the stroke volume (the amount of blood ejected from the heart with each beat). The body constantly strives to maintain an optimal cardiac output to meet its circulatory needs. When one of these two parameters (HR or SV) changes, the body will attempt to balance this system so that cardiac output remains optimal. For example, when heart rate increases, the stroke volume decreases (intuitively, this makes sense because the faster the heart beats, the less time it has to fill with blood). However, cardiac output will still be optimized for the body's needs at that moment. But what is more important for us now is understanding what happens when the heart rate decreases.
It is evident that in order to achieve an optimal cardiac output with a lower heart rate, the stroke volume must increase. This is exactly what is needed. If a person has a lower resting heart rate, it indicates that their heart is working more efficiently over time. The heart becomes stronger as a muscle and is forced to eject more blood with each beat. This fundamental physiological process holds true for healthy individuals and may change with the development of heart and vascular diseases. Therefore, it is crucial to understand the importance of striving for lower resting heart rate values.
Risks
Numerous studies have repeatedly shown that a high resting heart rate is an alarming signal of increased health risks, especially for the cardiovascular system. It is associated with an increased risk of cardiovascular diseases such as coronary artery disease and heart failure, increases the likelihood of heart attack and stroke, and shortens life expectancy. Additionally, a high heart rate can contribute to sleep disturbances, increased anxiety, and a decline in quality of life. To reduce these risks, it is important to monitor your heart rate and take steps to lower it, such as exercising regularly, eating a healthy diet, and managing stress.
For people with existing cardiovascular disease or complications, therapy is often prescribed to achieve a target heart rate, typically between 50 and 70 beats per minute.
Why a lower resting heart rate is beneficial
A lower resting heart rate reduces the aforementioned risks and increases both lifespan and quality of life.
When the heart is strong, it can pump more blood with each beat, meaning it doesn’t need to beat as frequently to meet the body’s demands. A lower resting heart rate indicates that the heart is pumping blood more efficiently. It’s a hallmark of good cardiovascular health.
Over a lifetime, the heart will beat billions of times. A lower resting heart rate means the heart is working less frequently, reducing the stress and strain on the heart muscles and the arterial walls. This reduced workload can potentially extend the life of the heart.
A lower resting heart rate is often associated with lower blood pressure. When the heart beats less frequently, it exerts less force on the blood vessels, reducing the risk of hypertension. Maintaining healthy blood pressure is crucial for preventing strokes, heart attacks, and kidney disease.
Efficient blood circulation ensures that the body’s tissues receive a steady supply of oxygen and nutrients, improving overall energy levels, cognitive function, and physical performance.
Like any muscle, the heart can be trained. Regular exercise, particularly aerobic activities like running, swimming, and cycling, can lower your resting heart rate over time. This reduction is a sign of improved physical fitness and endurance, as the heart becomes more efficient at pumping blood.
Conclusion
It is crucial to understand and maintain a lower resting heart rate to ensure long-term cardiovascular health and overall well-being. Regular exercise, a balanced diet, and effective stress management are the keys to significantly improving your heart's efficiency and reducing the risks associated with a high resting heart rate. As your heart becomes stronger and more efficient, your physical performance and energy levels will improve, contributing to a longer, healthier life. Prioritize these factors to lower your resting heart rate and improve your overall health.
References
Fox, K., Borer, J. S., Camm, A. J., Danchin, N., Ferrari, R., Lopez Sendon, J. L., Steg, P. G., Tardif, J. C., Tavazzi, L., Tendera, M., & Heart Rate Working Group (2007). Resting heart rate in cardiovascular disease. Journal of the American College of Cardiology, 50(9), 823–830. https://doi.org/10.1016/j.jacc.2007.04.079
Hori, M., & Okamoto, H. (2012). Heart rate as a target of treatment of chronic heart failure. Journal of cardiology, 60(2), 86–90. https://doi.org/10.1016/j.jjcc.2012.06.013
Libby P, Bonow RO, Mann DL, Tomaselli GF, Bhatt DL, Solomon SD, Braunwald E, eds. Braunwald's Heart Disease, Single Volume. 12th ed. Elsevier; 2022. ISBN: 9780323824675.
