Can a Low Resting Heart Rate Be Bad for You?

Trained athletes often have resting heart rates as low as 30-50 beats per minute, which is a sign of their highly efficient cardiovascular systems. This phenomenon is closely linked to the strength of their hearts and the increased stroke volume that allows for better oxygenation of tissues.

Exercise plays a significant role in this process. It not only improves cardiovascular efficiency but also leads to the release of erythropoietin, a hormone that increases red blood cell synthesis, as well as raises the levels of hemoglobin and myoglobin. These components enhance oxygen transportation and storage in muscles, contributing to better overall tissue oxygenation. Improved oxygenation reduces sympathetic nervous system activity, leading to a slower heart rate via increased parasympathetic outflow.

Despite these benefits, exercise also triggers protein breakdown during catabolism. However, post-exercise protein synthesis (anabolism) is more pronounced, stimulated by the release of growth hormone. This promotes overall protein synthesis and the production of irisin, a protein involved in fat breakdown through the browning of fat cells. Regular exercise leads to increased muscle mass and reduced fat content in the body.

My Personal Experience

As someone with a low resting heart rate (typically 47, dipping to 42 for short periods), I have found that drinking can raise it, while abstinence tends to lower it. This variation highlights the influence of various factors on heart rate. I also noticed that my resting heart rate fluctuates.

Due to concerns about a high heart rate read by my FitBit during a run, I consulted a cardiologist. She reviewed my sinus bradycardia diagnosis and conducted an ECG stress test. Thankfully, both the resting heart rate and ECG results were within normal limits. This annual check-up also allowed me to calibrate my FitBit, discovering that it read approximately 18 beats per minute higher than the ECG at higher heart rates. This was reassuring and unnecessary worry was alleviated.

Interestingly, I can now regularly achieve an average heart rate of 135 beats per minute or less during a 5k run. This was a notable improvement from previous years, demonstrating the positive impact of regular exercise on heart rate and overall cardiovascular health.

Expert Insight

The cardiologist would be concerned if an ECG showed irregularities in heart rate rhythm. In my case, the ECG results were clear, with no indications of any issues.

Elite cyclists often have extremely low resting heart rates below 36 beats per minute. Due to their highly oxygenated blood, which is thicker and more viscous, they experience difficulties during sleep. Athletes in this category often have to wake up at night to ride an exercise bike and maintain circulation, as their blood is excellent for oxygen transport but not ideal for resting.

Conclusion

If you are concerned about your resting heart rate, it is best to consult a physician. While my case is a positive example, every individual's health is unique, and only a medical professional can provide personalized advice. Remember, a low resting heart rate does not necessarily indicate a problem, but it is always wise to have it evaluated.