What High-Volume Exercise Means for Heart Health
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Many of us exercise to stay fit and protect our hearts. Regular physical activity is known to lower the risk of heart disease, diabetes, and high blood pressure. But what happens when we push our exercise to extreme levels, like running marathons or intense endurance training for hours each week? A new study sheds light on this important question—and the results may surprise you.
The Study: What Was It About?
Researchers looked at data from over 61,000 people, comparing athletes to nonathletes. They focused on subclinical coronary atherosclerosis—early signs of heart artery disease that don’t yet cause symptoms. Using advanced heart scans like coronary artery calcium (CAC) scores and CT angiography, they measured how much plaque had built up in the heart’s arteries.
The study compared people who exercised moderately (1,500–3,000 MET-min/week) and those with very high activity levels (over 3,000 MET-min/week). For reference, MET-min/week is a way to measure physical activity, combining exercise intensity and duration.
Key Findings: Men vs Women
The results showed a striking difference between men and women:
- Male athletes who exercised at very high levels had significantly higher CAC scores and more calcified plaque in their heart arteries than men who exercised less.
- Male athletes with moderate activity did not show this increase—they had similar or even better plaque profiles than nonathletes.
- Female athletes, even those with high activity levels, did not show increased CAC scores or plaque volume. In fact, women who exercised moderately or intensely tended to have fewer plaques and lower overall calcium buildup than nonathletic women.
This suggests that while intense exercise may lead to more heart artery calcification in men, it does not appear to carry the same risk for women.
Why Might This Be Happening?
The exact reasons aren't fully clear, but scientists have some theories:
- Shear stress: Repeated, intense exercise might cause small injuries to the blood vessel lining, triggering plaque buildup.
- Hormones: Male hormones like testosterone may play a role in how plaque forms.
- Calcium plaque stability: Some studies suggest that the plaques found in athletes may be more stable and less likely to rupture, which could make them less dangerous.
Should You Be Worried?
It’s important to keep this in perspective. While high-volume male athletes may have more calcified plaque, many still enjoy long, healthy lives. The type of plaque matters too—calcified plaques are usually more stable than soft plaques, which are more likely to rupture and cause heart attacks.
Also, regular moderate exercise remains highly beneficial for both men and women. The concern arises mainly when exercise volume becomes extremely high for many years, as seen in competitive endurance athletes.
Practical Takeaways
- Exercise regularly, but don’t overdo it: Aim for 150–300 minutes of moderate exercise per week unless you're training under professional guidance.
- Get heart screenings if you're a high-volume exerciser: Especially if you're a male athlete over 40, talk to your doctor about CAC scoring or a CT scan.
- Focus on overall health: Good sleep, a balanced diet, and stress management are just as important as your workout routine.
- Listen to your body: Fatigue, chest discomfort, or breathlessness should never be ignored—get checked out promptly.
Final Thoughts
This study highlights that more isn’t always better when it comes to exercise—at least not for everyone. While the benefits of regular activity are undeniable, ultra-endurance training may carry different risks for men and women. The key is balance: stay active, but be smart about how far you push your limits. Always consult your healthcare provider, especially if you're engaging in high-volume or high-intensity training.