Cyclists’ Heart Health: Balancing the Athlete’s Heart Against Overtraining

The benefits of cycling for heart health are well established — research shows that regular aerobic exercise can significantly reduce the risk of heart disease and extend lifespan. In recent years, however, studies have also pointed out that extreme endurance training may bring about unexpected changes to the heart. This article explores how to find the balance point that maximizes cardiac benefits while minimizing potential risks.

The Positive Effects of Exercise on the Heart

Beneficial Cardiac Adaptations

Regular aerobic training (especially cycling) causes the heart to undergo the adaptations known as “Athletic Heart”:

Resting heart rates of elite cyclists:

• Miguel Indurain (5-time Tour de France champion): resting heart rate of 28 bpm
• Lance Armstrong (controversial): resting heart rate of 32-34 bpm
• Average person: 60-80 bpm

Reduced Long-Term Risk of Heart Disease

The Potential Effects of Overtraining on the Heart

The “Reverse J-Curve” Theory

Researchers have proposed that the relationship between exercise volume and heart disease risk, in terms of cardiac health benefit, forms a “reverse J-curve”:

• Low exercise volume: high risk of heart disease
• Moderate exercise volume: lowest risk
• Very high exercise volume (professional athlete level): risk may rise slightly

Important: Even within the very-high-volume group, the risk remains far lower than for people who do not exercise at all.

Cardiac Research on Ultra-Endurance Exercise

Studies of athletes who have completed multiple triathlons, ultramarathons, or engaged in long-term, high-intensity training have found:

Important context: The subjects of these studies are typically extreme athletes who have completed multiple triathlons or ultramarathons, with training volumes far exceeding those of most amateur cyclists.

Recognizing Cardiac Warning Signs of Overtraining

Ordinary Fatigue vs. Cardiac Problems

One warning sign: resting heart rate persistently 10-15% above baseline
This is often an early indicator of overtraining or illness, and warrants reduced training volume and close observation.

Best Practices for Heart Rate Monitoring

Applying HRV (Heart Rate Variability)

HRV is currently the most effective tool for monitoring cardiac recovery status (previously introduced in our sleep management article).

The effect of summer heat: Taiwan’s summer heat lowers HRV — this is a normal autonomic nervous system response, and does not equate to overtraining.

Cardiac Drift

During long rides (especially in hot weather), heart rate gradually rises even when power output stays constant — this is called “cardiac drift”:

• Caused by dehydration and rising body temperature
• A normal phenomenon, not indicative of a cardiac problem
• A signal from your body reminding you to hydrate

What Age Requires Special Attention?

Special Considerations for Cyclists Over 40

After age 40, certain cardiac risk factors begin to rise:

• Increased risk of coronary artery disease
• Warning signs that should not be ignored: chest pain, jaw pain, arm numbness (atypical symptoms of heart disease)

Recommendation: Cyclists who begin serious training after age 40 should undergo an exercise stress test (ECG) before starting.

Caution for First-Time High-Intensity Events

Regardless of age, before participating in a high-intensity race or challenge for the first time (such as summiting Wuling or the Two Towers Challenge), confirm:

• Whether there is a family history of heart-related conditions
• Whether you have recently experienced unexplained chest tightness or palpitations
• Whether you undergo regular health checkups

A Positive Conclusion: Cycling Is a Friend to Heart Health

While all of this research raises some points worth paying attention to, the overall conclusion is clear:

Regular cycling — even serious amateur training — offers cardiac health benefits that far outweigh any potential risks.

The most important strategies for protecting your heart:

1. Increase training volume gradually (don’t ramp up intensity too quickly)
2. Ensure adequate recovery time (sleep, rest days)
3. Get regular health checkups (especially after age 40)
4. Listen to your body’s warning signs (any unusual cardiac symptoms warrant medical evaluation)

Cycling doesn’t just extend your lifespan — more importantly, it extends your “healthspan”: keeping your heart in optimal condition so you can enjoy everything cycling has to offer for years to come.

Related Reading

• Improving Cardiac Function Through Cycling: Long-Term Adaptations of Heart Structure from Regular Riding
• Cycling and Heart Health: The Protective Benefits of Long-Term Riding for the Heart
• Cycling and Cardiac Adaptation: The Long-Term Cardiovascular Benefits of Regular Riding
• The Comprehensive Impact of Cycling on Cardiovascular Health: A Summary of Medical Research