Can Too Much Exercise Harm Your Heart?
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When we talk about exercise, the message is usually clear: the more, the better. But in recent years, some studies have raised concerns that extremely high levels of endurance exercise—like long-distance running or cycling—might have a negative effect on heart health. Is there a limit to how much exercise is good for you?
A new study offers helpful answers and reassuring news for fitness lovers.
What Did the Study Look At?
Researchers wanted to see if people who exercise a lot—about 9 hours a week—had any negative effects on their heart health. They compared 100 people who trained regularly in endurance sports like running, cycling, and skiing, with 124 people who didn’t exercise at all (the sedentary group).
They used a special heart scan called coronary CTA to check for signs of heart disease, like blocked arteries or high-risk plaques. They also tracked these people for nearly 4 years to see if anyone had heart problems like heart attacks or needed medical procedures.
What Were the Results?
The good news: people who exercised a lot had no worse heart health than those who didn’t. In fact, they had fewer risk factors for heart disease.
Here’s what they found:
- Lower blood pressure: Fewer athletes had high blood pressure (37% vs. 54% in non-exercisers).
- Lower rates of diabetes: Only 5% of exercisers had diabetes, compared to nearly 14% in non-exercisers.
- Lower body weight: Their average BMI was healthier (24.3 vs. 28.2).
- Less smoking: Fewer athletes smoked or had recently quit.
Importantly, there were no differences in major heart scan results, like:
- Calcium buildup in arteries (a sign of aging or clogged arteries).
- Severity of artery narrowing.
- Presence of high-risk plaque.
Also, after 4 years, both groups had very low rates of heart attacks or other major heart events, showing that even with intense training, athletes weren’t at higher risk.
So Is More Exercise Always Better?
This study suggests that moderate-to-high levels of exercise, up to 9 hours per week, are safe for heart health—especially in recreational athletes, not elite professionals.
The research also supports the idea that exercise helps protect your heart by improving your overall health. It helps lower weight, blood sugar, blood pressure, and reduces smoking—all major contributors to heart disease.
But What About Professional Athletes?
Some earlier studies have shown that lifelong elite athletes might have more calcium in their heart arteries. However, the type of plaque they have may be less dangerous (more stable and calcified). In contrast, non-calcified plaque is more likely to rupture and cause heart attacks.
This new study mostly looked at recreational athletes—people who enjoy sports but don’t compete professionally. So, while the results are reassuring for most of us, they might not apply to people who train at extreme levels for decades.
What Can We Learn?
If you enjoy running, cycling, hiking, or other endurance sports—even several times a week—you can keep going without fear. According to this research:
- Exercise remains one of the best ways to prevent heart disease.
- High volumes of regular exercise (up to 9 hours per week) are not harmful to your heart.
- The real heart dangers are still high blood pressure, smoking, diabetes, and excess weight.
Practical Tips for Heart-Safe Exercise
- Stick with regular exercise: Aim for at least 150 minutes per week of moderate activity, or 75 minutes of vigorous activity.
- Listen to your body: If you feel chest pain, dizziness, or unusual fatigue, get it checked out.
- Don’t skip checkups: Especially if you’re over 40 or have risk factors like high blood pressure or family history of heart disease.
- Mix intensity: Vary your training between easy, moderate, and hard sessions. You don’t need to go “all out” all the time.
Final Thoughts
For most people, especially those who train for fun and fitness, exercising up to 9 hours a week is not just safe—it’s incredibly beneficial. This study helps take the worry out of your workouts. As long as you’re staying balanced and taking care of other health factors, your heart will thank you for moving more.